A375026 a(n) = [x^n] 2/(3*sqrt(4*x^2 + 1) + 6*x - 1). Alternating row sums of A375025.

1, -3, 6, -9, 12, -18, 30, -45, 60, -90, 156, -234, 288, -432, 846, -1269, 1260, -1890, 4980, -7470, 3912, -5868, 33996, -50994, -11688, 17532, 285720, -428580, -471480, 707220, 2950830, -4426245, -7902900, 11854350, 35254980, -52882470, -115143480, 172715220, 457385220

Offset

0,2

Links

Table of n, a(n) for n=0..38.

Maple

gf := 2/(3*sqrt(4*x^2 + 1) + 6*x - 1):
ser := series(gf, x, 42): seq(coeff(ser, x, n), n = 0..38);

Crossrefs

Cf. A375025.

Sequence in context: A232920 A092421 A381838 * A109657 A175589 A348339

Adjacent sequences: A375023 A375024 A375025 * A375027 A375028 A375029

Keyword

sign

Author

Peter Luschny, Aug 07 2024

Status

approved