18639

Appears in sequences

• Let [n] = {1,2,...,n}. Let G_n be the union of all closed line segments joining any two elements of [n] X [n] along a vertical or horizontal line, or along a line with slope +-1. Then a(n) = combined total of the number of (nondegenerate) triangles and rectangles for which all edges are subsets of G_n.at n=11A098921
• Number of up steps starting at an odd level in all nondecreasing Dyck paths of semilength n. A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.at n=9A121525
• 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), (0, 0, -1), (0, 1, 1), (1, 0, 0)}.at n=8A150159
• Numbers that match polynomials over {0,1} that have a factor containing -3 as a coefficient; see Comments.at n=26A208182
• Expansion of x * f(-x^7) * f(-x^21) / (f(-x) * f(-x^3)) where f() is a Ramanujan theta function.at n=31A226007
• a(n) = 591*2^n - 273.at n=5A278131
• a(0)=0, then a(n) = smallest odd k > a(n-1) such that 6*k^prime(n)-1 is prime.at n=42A283676
• Sequences n*(n+1)*(6*n+1)/2 and n*(n+1)*(7*n+1)/2 interleaved.at n=35A296636
• Composite numbers k coprime to 13 such that k divides A006190(k) - Kronecker(13,k).at n=24A327654
• Primitive terms of A359563: terms of A359563 with no proper divisor in A359563.at n=34A359564