A326724 - OEIS

A326724

Triangle with Euler (secant) numbers, read by rows, T(n, k) for 0 <= k <= n.

1, -1, 1, 5, -10, 5, -61, 183, -183, 61, 1385, -5540, 8310, -5540, 1385, -50521, 252605, -505210, 505210, -252605, 50521, 2702765, -16216590, 40541475, -54055300, 40541475, -16216590, 2702765, -199360981, 1395526867, -4186580601, 6977634335, -6977634335, 4186580601, -1395526867, 199360981

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OFFSET

0,4

LINKS

Table of n, a(n) for n=0..35.

FORMULA

T(n, k) = (2*n)! [x^k] [y^(2*n)] sec(y*sqrt(x - 1)).

Sum_{k=0..n} (-1)^(n-k)*T(n, k) = |A012816(n+1)|.

EXAMPLE

Triangle starts:

[0] 1;

[1] -1, 1;