28146

Appears in sequences

• G.f.: (x+4*x^3+x^5)/((1-x)^2*(1-x^2)^2*(1-x^3)^2).at n=26A083708
• Number of subsets of {1, ..., n} that are sum-free but not double-free.at n=23A088811
• Number of simple permutations of degree n.at n=8A111111
• Numbers n such that n*2^2281 - 1 is prime.at n=25A265504
• a(n) is the smallest positive integer which can be represented as the sum of distinct nonzero n-gonal pyramidal numbers in exactly n ways, or 0 if no such integer exists.at n=15A350210
• E.g.f. satisfies A(x) = 1 + x*A(x)^3 * (exp(x*A(x)^2) - 1).at n=6A371271