41850

Appears in sequences

• Number of rooted planar maps with 4 vertices and n faces and no isthmuses.at n=4A006421
• Numbers k such that the set of prime divisors of k is equal to the set of prime divisors of sigma(k).at n=20A027598
• Number of labeled n-element posets with no 3-element antichain.at n=6A080687
• Partial sums of n 3-spaced triangular numbers beginning with t(2), e.g., a(2) = t(2) + t(5) = 3 + 15 = 18.at n=29A085789
• Solution to the non-squashing boxes problem (version 2).at n=38A089055
• Numbers n with following property: suppose n^6 = d1 d2 d3 ...dk in decimal; then d1! + d2! + ... + dk! is a square.at n=18A130688
• a(n) = 6*n^2*(2*n + 1).at n=15A190705
• Number of (w,x,y,z) with all terms in {1,...,n} and |x-y|=|y-z|+1.at n=31A212680
• Numbers k such that k divides 1 + Sum_{j=1..k} prime(j)^11.at n=14A233193
• Triangle read by rows: T(n, k) = Sum_{t=k..n-3} (-1)^(t-k)*(n-t)!*binomial(t,k)*binomial(n-3,t).at n=23A264028
• Numbers k such that the squarefree kernel of sigma(k) is equal to the squarefree kernel of 2*k.at n=21A332208
• Triangle read by rows: T(n,k) is the number of rooted planar maps with n edges, k faces and no isthmuses, n >= 0, k = 1..n+1.at n=41A342981
• a(n) is the number of integer triples (x,y,z) satisfying a system of linear inequalities and congruences specified in the comments.at n=44A370349