A037548 Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 1,2,2.

1, 9, 65, 456, 3194, 22360, 156521, 1095649, 7669545, 53686816, 375807714, 2630654000, 18414578001, 128902046009, 902314322065, 6316200254456, 44213401781194, 309493812468360, 2166456687278521, 15165196810949649, 106156377676647545, 743094643736532816, 5201662506155729714

Offset

1,2

Links

Table of n, a(n) for n=1..23.

Index entries for linear recurrences with constant coefficients, signature (7,0,1,-7).

Formula

G.f.: x*(1+2*x+2*x^2) / ( (x-1)*(7*x-1)*(1+x+x^2) ). - R. J. Mathar, Apr 30 2015

E.g.f.: (exp(-x/2)*(30*cos(sqrt(3)*x/2) - 2*sqrt(3)*sin(sqrt(3)*x/2)) + 65*exp(7*x) - 95*exp(x))/342. - Stefano Spezia, Feb 12 2025

Crossrefs

Sequence in context: A081040 A102902 A127534 * A238275 A381024 A287816

Adjacent sequences: A037545 A037546 A037547 * A037549 A037550 A037551

Keyword

nonn,base,easy

Author

Clark Kimberling

Extensions

More terms from Michel Marcus, Feb 12 2025

Status

approved