32689

Appears in sequences

• a(n) = a(n-1) + 3*a(n-2) for n > 1, a(0) = a(1) = 1.at n=13A006130
• Strong pseudoprimes to base 54.at n=17A020280
• Strong pseudoprimes to base 65.at n=21A020291
• Expansion of 1/(1 - 7*x + 9*x^2).at n=6A099459
• a(n) = Sum_{k=0..floor(n/2)} binomial(n-k, k-1) * 3^(k-1).at n=14A099579
• Expansion of g.f. x^2/(1 - 2*x - 25*x^2).at n=7A123004
• a(n) = (-1)*a(n-1) + 3*a(n-2) with a(1)=-1 and a(2)=1.at n=13A140167
• Numbers with all different digits such that each digit leaves the same nonzero remainder when each is divided into the number.at n=15A152852
• Numbers m such that the Stern polynomial B(m,x) is irreducible and self-reciprocal.at n=19A186893
• Irregular triangle read by rows: T(n,k) is the number of permutations in C_n (= the 1-cycles in S_n) having k stretching pairs.at n=48A216121
• Hilltop maps: number of nX3 binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 nX3 array.at n=4A218633
• T(n,k)=Hilltop maps: number of nXk binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 nXk array.at n=25A218638
• Hilltop maps: number of 5Xn binary arrays indicating the locations of corresponding elements not exceeded by any horizontal, diagonal or antidiagonal neighbor in a random 0..3 5Xn array.at n=2A218640
• Smaller of two consecutive semiprimes which are anagrams of each other.at n=14A228135
• Number of (non-null) connected induced subgraphs of the complete tripartite graph K_{n,n,n}.at n=4A290756
• Let phi be the one-to-one mapping between binary trees and natural numbers described in the Tychonievich link. Let a(n) = min({phi^{-1}(t)| size(t)=n}); i.e., a(n) is the rank -- starting from 0 -- of the first tree the size of which is n.at n=22A296689
• a(n) = 2^(n+3) - 6*n - 7.at n=12A320661
• 9-gonal numbers that are semiprimes.at n=12A356424