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A362154
Expansion of 1/(1 + x * sqrt(1-4*x)).
2
1, -1, 3, -3, 11, -5, 51, 35, 335, 689, 3055, 9073, 33891, 114425, 413623, 1464661, 5304803, 19199859, 70161499, 257270227, 948639463, 3511150611, 13047799395, 48649126799, 181968324231, 682577156519, 2567180111683, 9678596662499, 36571577629911
OFFSET
0,3
FORMULA
a(n) = (-1)^n * Sum_{k=0..n} 4^k * binomial((n-k)/2,k).
PROG
(PARI) my(N=30, x='x+O('x^N)); Vec(1/(1+x*sqrt(1-4*x)))
CROSSREFS
KEYWORD
sign,easy
AUTHOR
Seiichi Manyama, Apr 09 2023
STATUS
approved