A340495 Records in first differences of A340494.

2, 3, 8, 33, 138, 563, 2268, 9093, 36398, 145623, 582528, 2330153, 9320658, 37282683, 149130788, 596523213, 2386092918, 9544371743, 38177487048, 152709948273, 610839793178, 2443359172803

Offset

1,1

Links

Table of n, a(n) for n=1..22.

Rémy Sigrist, C program for A340495

Formula

The sequence a(n)-4*a(n-1) appears to be -5, -4, 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, ... which is essentially 5*k+1 (k >= -1). The sequence itself appears to have g.f. =

x*(2*x-1)*(2*x^2+5*x-2)/((1-x)^2*(1-4*x)).

Prog

(C) See Links section.

Crossrefs

Cf. A340488, A340494.

Sequence in context: A162074 A162052 A082569 * A084908 A078742 A005370

Adjacent sequences: A340492 A340493 A340494 * A340496 A340497 A340498

Keyword

nonn,more

Author

Rémy Sigrist and N. J. A. Sloane, Jan 10 2021

Status

approved