65690

Appears in sequences

• Numbers n such that sigma(n)=2n-phi(phi(n)).at n=32A110073
• Number of (n+1) X (n+1) -10..10 symmetric matrices with every 2 X 2 subblock having sum zero and two distinct values.at n=17A211813
• Numbers k such that the coefficient of x^k in the expansion of Product_{m >= 1} (1-x^m)^15 is zero.at n=17A322043
• G.f.: Product_{k>=1} (1 + x^(2*k^2)) / (1 - x^k).at n=39A385009