220417

Appears in sequences

• Numbers k such that 127*2^k - 1 is prime.at n=4A050589
• Number of partitions of {1,..,n} into any number of lists of size not equal to 2, where a list means an ordered subset, cf. A000262.at n=8A113235
• Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (1, -1, -1), (1, 0, 1), (1, 1, -1)}.at n=11A148827
• Smallest composite m such that m and the smallest prime divisor of m begin with n.at n=21A197817
• Triangular array read by rows. T(n,k) is the number of sets of lists (as in A000262(n)) with exactly k size 2 lists, n >= 0, 0 <= k <= floor(n/2).at n=20A351823