cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A127945 Hankel transform of central coefficients of (1+k*x-2x^2)^n, k arbitrary integer.

Table of values

n a(n)
0 1
1 -4
2 -32
3 512
4 16384
5 -1048576
6 -134217728
7 34359738368
8 17592186044416
9 -18014398509481984
10 -36893488147419103232
11 151115727451828646838272
12 1237940039285380274899124224
13 -20282409603651670423947251286016

List of values

[1, -4, -32, 512, 16384, -1048576, -134217728, 34359738368, 17592186044416, -18014398509481984, -36893488147419103232, 151115727451828646838272, 1237940039285380274899124224, -20282409603651670423947251286016]

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

Content is available under The OEIS End-User License Agreement.