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Series question

  1. Nov 16, 2004 #1
    I have a programming assignment to fill an array with this series: 1,4, 9, 25, 36, …. The problem is I don't know what this series is so I can't write the program. Can anyone help?
  2. jcsd
  3. Nov 16, 2004 #2


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    looks like a mistake to me, I think it should be 1,4,9,16,25,36 therefore: an = n2
  4. Nov 16, 2004 #3
    I guess thats why it was giving me so much trouble. Thanks.
  5. Nov 16, 2004 #4
    hmmm :S

    http://www.research.att.com/~njas/sequences/eisBTfry00055.txt [Broken]

    %I A063577
    %S A063577 1,4,9,25,36,54,45,56,68,106,87,98,100,203,140,154,160,174,165,263,246,
    %T A063577 243,157,234,276,280,338,308,343,371,335,299,427,394,497,475,473,405,
    %U A063577 524,467,577,485,586,509,492,644,464,677,563,616,582
    %N A063577 Smallest power of 4 having just n 2's in its decimal representation.
    %t A063577 a = {}; Do[k = 1; While[ Count[ IntegerDigits[4^k], 2] != n, k++ ]; a = Append[a, k],{n, 0, 50} ]; a
    %Y A063577 Adjacent sequences: A063574 A063575 A063576 this_sequence A063578 A063579 A063580
    %Y A063577 Sequence in context: A045967 A030140 A062503 this_sequence A087058 A046659 A063760
    %K A063577 base,nonn
    %O A063577 0,2
    %A A063577 Robert G. Wilson v (rgwv(AT)rgwv.com), Aug 10 2001

    %I A087058
    %S A087058 4,9,25,36,64,81,100,144,169,225,256,289,361,400,484,529,625,676,729,
    %T A087058 841,900,1024,1089,1156,1296,1369,1521,1600,1764,1849,1936,2116,2209,
    %U A087058 2401,2500,2601,2809,2916,3136,3249,3364,3600,3721,3969,4096,4356,4489
    %N A087058 Smallest square number greater than 2*n^2.
    %F A087058 A087058(n) = A087057(n)^2 = (1 + A001951(n))^2 = (1 + floor[n*sqrt(2)])^2
    %e A087058 A087058(10) = 225 because 225 is the smallest square number greater than 2*10^2 = 200.
    %Y A087058 Cf. A001951, A087055, A087056, A087057, A087059, A087060.
    %Y A087058 Adjacent sequences: A087055 A087056 A087057 this_sequence A087059 A087060 A087061
    %Y A087058 Sequence in context: A030140 A062503 A063577 this_sequence A046659 A063760 A046451
    %K A087058 easy,nonn
    %O A087058 1,1
    %A A087058 Jens Voss (jens(AT)voss-ahrensburg.de), Aug 07 2003

    %I A046659
    %S A046659 1,4,9,25,36,100,121,225,289,484,529,841,900,1089,1156,1681,2116,2209,
    %T A046659 2601,2809,3364,3481,4356,4761,5041,6724,6889,7225,7569,7921,8836,
    %U A046659 10201,10404,11236,11449,12769,13225,13924,15129,17161,18769,19044
    %N A046659 Sum of divisors and sum of cubes of divisors are relatively prime.
    %C A046659 It appears that (a) all the numbers are squares, (b) the number of divisors is a power of 3.
    %C A046659 It can be shown that this is a subset of A028982.
    %e A046659 x=100 with 9 divisors whose sum is 217=7*31 and sum of cubes of divisors is 1149823=19*73*829; GCD[ 217,1149823 ]=1
    %Y A046659 Cf. A028982, A046679 - A046981, A046983, A046985.
    %Y A046659 Adjacent sequences: A046656 A046657 A046658 this_sequence A046660 A046661 A046662
    %Y A046659 Sequence in context: A062503 A063577 A087058 this_sequence A063760 A046451 A082200
    %K A046659 nonn
    %O A046659 1,2
    %A A046659 Labos E. (labos(AT)ana1.sote.hu)
    Last edited by a moderator: Apr 21, 2017 at 10:13 AM
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