A370779 Expansion of ( (1 + x)*(1 - 5*x)*(1 + 25*x) )^(1/3).

1, 7, -84, 1020, -17220, 313068, -6075444, 122709468, -2553130020, 54317619660, -1175968479252, 25819593611196, -573476704909572, 12861006710141100, -290799326551852020, 6621725329384239516, -151707434284857934308, 3494405505576163607436

Offset

0,2

Comments

The cube root of F(x) = (1 + x)*(1 - (3*k+2)*x)*(1 + (3*k+2)^2*x) is an integer series because F(x) == (1+x)*(1 + 2*x - 8*x^2) == (1+x)^3 (mod 9).

Links

Table of n, a(n) for n=0..17.

Prog

(PARI) my(N=20, x='x+O('x^N)); Vec(((1+x)*(1-5*x)*(1+25*x))^(1/3))

Crossrefs

Cf. A370145, A370149, A370780.

Cf. A370782.

Sequence in context: A177009 A099674 A067413 * A166178 A346582 A234510

Adjacent sequences: A370776 A370777 A370778 * A370780 A370781 A370782

Keyword

sign

Author

Seiichi Manyama, Mar 01 2024

Status

approved