A037492 Base 7 digits are, in order, the first n terms of the periodic sequence with initial period 2,1.

2, 15, 107, 750, 5252, 36765, 257357, 1801500, 12610502, 88273515, 617914607, 4325402250, 30277815752, 211944710265, 1483612971857, 10385290803000, 72697035621002, 508879249347015, 3562154745429107, 24935083218003750, 174545582526026252, 1221819077682183765

Offset

1,1

Links

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

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

Formula

a(n) = 7*a(n-1) + a(n-2) - 7*a(n-3).

G.f.: x*(2+x) / ( (x-1)*(7*x-1)*(1+x) ). - R. J. Mathar, Nov 21 2011

a(n) = floor(5*7^n/16). - Christian Krause, May 30 2026

E.g.f.: (5*(cosh(7*x) - cosh(x) + sinh(7*x)) - 3*sinh(x))/16. - Stefano Spezia, May 30 2026

Crossrefs

Sequence in context: A037733 A308938 A037556 * A037572 A218686 A279087

Adjacent sequences: A037489 A037490 A037491 * A037493 A037494 A037495

Keyword

nonn,base,easy

Author

Clark Kimberling

Extensions

a(20)-a(22) from Christian Krause, May 30 2026

Status

approved