{if n is the sum of the first a natural numbers then it is a triangular number}eg 6=1+2+3(adsbygoogle = window.adsbygoogle || []).push({});

{a is any integer }show that m!+1is a perfect square if and only if m!/8 is a triangular number.m!/8 is a triangular number.so m!=o(mod8) therefore m has to be minimum 4 and not a multiple of 3.

**Physics Forums - The Fusion of Science and Community**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# See this

**Physics Forums - The Fusion of Science and Community**