A047353 Numbers that are congruent to {1, 2} mod 7.

1, 2, 8, 9, 15, 16, 22, 23, 29, 30, 36, 37, 43, 44, 50, 51, 57, 58, 64, 65, 71, 72, 78, 79, 85, 86, 92, 93, 99, 100, 106, 107, 113, 114, 120, 121, 127, 128, 134, 135, 141, 142, 148, 149, 155, 156, 162, 163, 169, 170

Offset

1,2

Links

David Lovler, Table of n, a(n) for n = 1..1000

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

Formula

From R. J. Mathar, Oct 08 2011: (Start)

a(n) = 7*n/2 - 15/4 - 5*(-1)^n/4.

G.f.: x*(1 + x + 5*x^2) / ( (1+x)*(x-1)^2 ). (End)

E.g.f.: 5 + ((14*x -15)*exp(x) - 5*exp(-x))/4. - David Lovler, Sep 11 2022

Mathematica

LinearRecurrence[{1, 1, -1}, {1, 2, 8}, 50] (* Harvey P. Dale, Nov 29 2014 *)

Prog

(PARI) a(n) = (14*n - 15 - 5*(-1)^n)/4 \\ David Lovler, Sep 11 2022

Crossrefs

Sequence in context: A073606 A305177 A327299 * A032928 A287564 A158458

Adjacent sequences: A047350 A047351 A047352 * A047354 A047355 A047356

Keyword

nonn,easy

Author

N. J. A. Sloane

Status

approved