180620

Appears in sequences

• A sequence related to the even-indexed Catalan numbers.at n=9A098469
• Column 6 of array illustrated in A089574 and related to A034261.at n=10A107601
• A vector recursion designed around a factorial row sum : v(n)=if[odd,{1.n,n^2,...,n!-Sum[2^m,{m,0,n/2-1}],n!-Sum2^m,{m,0,n/2-1}],...n^2.n,1}],if[ even{1.n,n^2,...,n!-2Sum[2^m,{m,0,n/2-1}],...n^2.n,1}].at n=49A152937
• A vector recursion designed around a factorial row sum : v(n)=if[odd,{1.n,n^2,...,n!-Sum[2^m,{m,0,n/2-1}],n!-Sum2^m,{m,0,n/2-1}],...n^2.n,1}],if[ even{1.n,n^2,...,n!-2Sum[2^m,{m,0,n/2-1}],...n^2.n,1}].at n=50A152937