This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A175915 #9 May 13 2013 01:49:15 %S A175915 2205,312896925,1874196225,3356107425,4181881725,4987853325, %T A175915 6946213725,8860349025,13250605725,17989980525,25443641025, %U A175915 32177090925,38286871425,55531730925,75756402225,113679103725,152738872209,170812073025,179835853725,186091427025 %N A175915 Odd terms of A109510. %C A175915 a(1)=2205=A109510(29), a(2)-a(8) from Max Alekseyev. %C A175915 sqrt(sigma(a(n))-2*a(n)): 6, 3432, 8250, 11022, 19376. %o A175915 (PARI) is(n)=n%2&&issquare(sigma(n)-2*n) \\ _Charles R Greathouse IV_, Dec 06 2011 %Y A175915 Cf. A109510 sigma(n)-2n is a square. %K A175915 nonn %O A175915 1,1 %A A175915 _Zak Seidov_, Oct 15 2010 %E A175915 a(6)-a(18) from _Donovan Johnson_, Oct 17 2010 %E A175915 a(19)-a(20) from _Donovan Johnson_, Dec 06 2011