A037566 Base 9 digits are, in order, the first n terms of the periodic sequence with initial period 2,2,1.

2, 20, 181, 1631, 14681, 132130, 1189172, 10702550, 96322951, 866906561, 7802159051, 70219431460, 631974883142, 5687773948280, 51189965534521, 460709689810691, 4146387208296221, 37317484874665990, 335857363871993912, 3022716274847945210, 27204446473631506891, 244840018262683562021

Offset

1,1

Links

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

Index entries for linear recurrences with constant coefficients, signature (9,0,1,-9).

Formula

G.f.: x*(2+2*x+x^2) / ( (x-1)*(9*x-1)*(1+x+x^2) ). - R. J. Mathar, Apr 30 2015

E.g.f.: exp(-x/2)*(543*exp(19*x/2) - 455*exp(3*x/2) - 88*cos(sqrt(3)*x/2)- 72*sqrt(3)*sin(sqrt(3)*x/2))/2184. - Stefano Spezia, Sep 13 2025

Crossrefs

Sequence in context: A105493 A067641 A279462 * A125857 A226312 A171076

Adjacent sequences: A037563 A037564 A037565 * A037567 A037568 A037569

Keyword

nonn,base,easy

Author

Clark Kimberling

Extensions

a(18)-a(22) from Stefano Spezia, Sep 13 2025

Status

approved