42081

Appears in sequences

• Number of 5-tuples of different integers from [ 2,n ] with no common factors among quadruples.at n=24A015645
• Inverted (definition in A075193) generalized tribonacci numbers A001644.at n=32A075298
• a(n) = number of Egyptian fractions 1 = 1/x_1 + ... + 1/x_k (for any k), 0<x_1<...<x_k=n.at n=55A092669
• Nonzero elements of A092669.at n=19A092672
• Numbers k such that 10^k + 81 is prime.at n=16A137848
• a(n) = a(n-1) + a(n-2) + a(n-3), with a(0) = 1, a(1) = a(2) = 7.at n=16A214829
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 417", based on the 5-celled von Neumann neighborhood.at n=41A272018
• Expansion of Product_{k>=1} (1 + x^(2*k-1))^(k*(k-1)/2).at n=35A294777