18469

Appears in sequences

• Numbers k such that k, k+1, k+2 and k+3 have the same number of divisors.at n=21A006601
• Odd 9-gonal (or enneagonal) numbers.at n=36A028991
• a(n) = (2*n+1)*(7*n+1).at n=36A033572
• Numbers k such that gcd(3k,8^k+1) = 3 but k does not divide the numerator of B(2k) (the Bernoulli numbers).at n=28A070193
• a(n) is the numerator of the sum of the reciprocals of the positive integers k, k<=n, where every positive integer <= k and coprime to k is also coprime to n.at n=26A126261
• a(n) = Sum_{i=0..n} digsum(i)^3, where digsum(i) = A007953(i).at n=46A231688
• Number of partitions of n such that (number parts having multiplicity 1) is a part and (number of parts > 1) is a part.at n=47A241511
• Number of (n+1) X (1+1) 0..1 arrays with every 2 X 2 subblock diagonal minus antidiagonal sum nondecreasing horizontally and vertically.at n=11A253152
• Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 637", based on the 5-celled von Neumann neighborhood.at n=24A273306
• Number of distinct sums of n complex n-th roots of 1.at n=8A299754
• Nonsemiprimes in A306097 = A121707 \ A267999.at n=24A321488