-2117

Appears in sequences

• Values of n such that L(4) and N(4) are both prime, where L(k) = (n^2+n+1)*2^(2*k) + (2*n+1)*2^k + 1, N(k) = (n^2+n+1)*2^k + n.at n=30A226924
• Product_{n>=1} (1 + a(n)*x^n) = 1 + Sum_{n>=1} sigma(n)*x^n, where sigma = A000203.at n=17A353924