A047358 Numbers that are congruent to {2, 3} mod 7.

2, 3, 9, 10, 16, 17, 23, 24, 30, 31, 37, 38, 44, 45, 51, 52, 58, 59, 65, 66, 72, 73, 79, 80, 86, 87, 93, 94, 100, 101, 107, 108, 114, 115, 121, 122, 128, 129, 135, 136, 142, 143, 149, 150, 156, 157, 163, 164, 170

Offset

1,1

Links

Michael De Vlieger, Table of n, a(n) for n = 1..10000

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

Formula

a(n) = 7*n - a(n-1) - 9, n > 1. - Vincenzo Librandi, Aug 05 2010

G.f.: x*(2+x+4*x^2) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Dec 04 2011

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

Mathematica

Select[Range@ 170, MemberQ[{2, 3}, Mod[#, 7]] &] (* or *)
Fold[Append[#1, 7 #2 - Last@ #1 - 9] &, {2}, Range[2, 49]] (* or *)
Rest@ CoefficientList[Series[x (2 + x + 4 x^2)/((1 + x) (x - 1)^2), {x, 0, 49}], x] (* Michael De Vlieger, Jan 12 2018 *)

Crossrefs

Sequence in context: A279549 A030743 A098020 * A280731 A353614 A352198

Adjacent sequences: A047355 A047356 A047357 * A047359 A047360 A047361

Keyword

nonn

Author

N. J. A. Sloane

Status

approved