31485
domain: N
Appears in sequences
- n satisfying sigma(n+1) = sigma(n-1).at n=35A055574
- Numbers k such that sigma(k-1) divides sigma(k+1).at n=41A067130
- Numbers k such that k and 2*k, taken together are pandigital.at n=27A115922
- Subtriangle of generalized Catalan triangle CM(1,2) = A116880.at n=22A116872
- Generalized Catalan triangle, called CM(1,2).at n=29A116880
- Expansion of 1/(1 - x^3 - x^4 + x^7 - x^10 - x^11 + x^14) (a Salem polynomial).at n=64A143644
- Numbers n such that sigma(n+1) - sigma(n-1) = k*n for some integer k, where sigma(n) = A000203 (sum of divisors of n).at n=36A223137
- Numbers k such that sigma(k+1) divides sigma(k-1).at n=38A227304
- G.f.: 1/(1 + (x+x^2 + x)/(1 + (x+x^2 + x^2)/(1 + (x+x^2 + x^3)/(1 + (x+x^2 + x^4)/(1 + ...))))), a continued fraction.at n=19A352234