cp's OEIS Frontend

Examples

			Let p(k,n) be the number of 2k-cycles in the n X n grid graph for n >= k-1. p(k,n) are quadratic polynomials in n, with the first few given by:
  p(1,n) =      0,
  p(2,n) =      1 -      2*n +       n^2,
  p(3,n) =      4 -      6*n +     2*n^2,
  p(4,n) =     26 -     28*n +     7*n^2,
  p(5,n) =    164 -    140*n +    28*n^2,
  p(6,n) =   1046 -    740*n +   124*n^2,
  p(7,n) =   6672 -   4056*n +   588*n^2,
  p(8,n) =  42790 -  22904*n +  2938*n^2,
  p(9,n) = 275888 - 132344*n + 15268*n^2,
  ...
The linear coefficients give a(n), so the first few are 0, 2, 6, 28, 140, .... - _Eric W. Weisstein_, Apr 05 2018