20332

Appears in sequences

• a(n) = binomial(n+2,2) + binomial(n+3,3) + binomial(n+4,4) + binomial(n+5,5).at n=15A027659
• Intrinsic 10-palindromes: n is an intrinsic k-palindrome if it is a k-digit palindrome in some base.at n=18A060947
• a(n) = (prime(n)^4 - 1) / 240.at n=11A089034
• Numbers n such that p(n),p(n)+6,p(n)+12,p(n)+18 are consecutive primes and p(n)=6*k+1 for some k, where p(n) denotes n-th prime.at n=31A090838
• a(n) = J_4(n)/240.at n=41A115002
• Level of the first leaf (in preorder traversal) of a binary tree, summed over all binary trees with n edges. A binary tree is a rooted tree in which each vertex has at most two children and each child of a vertex is designated as its left or right child.at n=7A120989
• Expansion of psi(-x^3) / phi(-x) in powers of x where psi(), phi() are Ramanujan theta functions.at n=26A132218
• a(4n+1)=2a(4n), a(4n+2)=2a(4n+1), a(4n+3)=2a(4n+2), a(4n+4)=2a(4n+3)+A007583(n).at n=18A139784
• First differences of A139784.at n=18A139785
• The Wiener index of the P_3 X P_n grid, where P_m is the path graph on m nodes. The Wiener index of a connected graph is the sum of distances between all unordered pairs of nodes in the graph.at n=22A180569
• Numbers k such that (7*10^(2*k+1) - 9*10^k - 7)/9 is prime.at n=9A183181
• Smallest multiple of n whose factorial digit sum equals n.at n=16A191895
• Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 246", based on the 5-celled von Neumann neighborhood.at n=28A287135
• a(n) is the smallest m such that p = n-th popular prime = A385503(n) is popular on the interval [2,m].at n=6A289661
• Triangle read by rows related to Catalan triangle A009766.at n=47A293944
• Triangle read by rows related to Catalan triangle A009766.at n=52A293944
• The primitive abundant numbers k (A071395) arranged by the decreasing values of their abundancy index sigma(k)/k.at n=14A307098
• Number of regions in a regular n-gon with all diagonals drawn whose edges all have a different number of facing edges.at n=43A350718