418609

Appears in sequences

• Number of ways to place non-intersecting diagonals in convex n-gon so as to create no triangles.at n=15A046736
• Numbers k such that sigma_4(k)/sigma_2(k) is prime.at n=31A066109
• Squares which repeat with at least two full periods when written in base 2.at n=4A071128
• Squares which repeat with at least two full periods when written in base 8.at n=4A071134
• Squares for which both the sum of the digits and the product of the digits is a triangular number.at n=34A118490
• G.f.: 1/[(1-2x)(1+2x+3x^2)].at n=20A122508
• Squares in A111153.at n=33A175255
• Number of n X 4 0..1 arrays avoiding 0 0 1 and 0 1 1 horizontally and 0 0 1 and 1 1 0 vertically.at n=23A207399
• Perfect squares which can be written neither as a^2+b^2, nor as a^2+2*b^2, nor as a^2+3*b^2, nor as a^2+7*b^2, with a > 0 and b > 0.at n=7A216408
• Number of positive integer solutions to the Diophantine equation x + y + 2z = n^2.at n=35A218832
• a(n) = (1-2*n^2)^2.at n=18A239607
• Numbers k such that sigma(k^3) is prime.at n=23A279096
• Little Hankel transform of A317614: a(n) = A317614(n+1)^2 - A317614(n)*A317614(n+2).at n=35A381374