21274

Appears in sequences

• Stella octangula numbers: a(n) = n*(2*n^2 - 1).at n=22A007588
• Numbers k such that in k and k^2 the parity of digits alternates.at n=39A030153
• a(0) = a(1) = 1. a(n) = a(n-1) + a(n - b(n)), where b(n) is largest prime dividing n.at n=37A137809
• a(n) = 2662*n - 22.at n=7A157609
• Number of (n+2) X 3 binary arrays with each 3 X 3 subblock having rows and columns in lexicographically nondecreasing order.at n=39A184540
• Poincaré series for invariant polynomial functions on the space of binary forms of degree 9.at n=25A293934
• Sum of the next n nonnegative integers repeated (A004526).at n=43A319007
• Expansion of Sum_{k>0} x^(2*k)/(1-x^k)^6.at n=17A363606