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.

A341106 a(n) = 2^n*E2poly(n, -1/2), where E2poly(n, x) = Sum_{k=0..n} A340556(n, k)*x^k, are the second-order Eulerian polynomials.

Table of values

n a(n)
0 1
1 -1
2 0
3 6
4 -12
5 -144
6 1080
7 5184
8 -127008
9 95904
10 19077120
11 -154929024
12 -3210337152
13 70284900096
14 391453171200
15 -30354545511936
16 153830450875392
17 13189520200402944
18 -244127117929789440
19 -5109022268709986304
20 237988748560571301888
21 571783124036801765376

List of values

[1, -1, 0, 6, -12, -144, 1080, 5184, -127008, 95904, 19077120, -154929024, -3210337152, 70284900096, 391453171200, -30354545511936, 153830450875392, 13189520200402944, -244127117929789440, -5109022268709986304, 237988748560571301888, 571783124036801765376]