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A047356 Numbers that are congruent to {1, 3} mod 7. 5
1, 3, 8, 10, 15, 17, 22, 24, 29, 31, 36, 38, 43, 45, 50, 52, 57, 59, 64, 66, 71, 73, 78, 80, 85, 87, 92, 94, 99, 101, 106, 108, 113, 115, 120, 122, 127, 129, 134, 136, 141, 143, 148, 150, 155, 157, 162, 164, 169 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This sequence is related to A010702 by a(n) = (Sum_{i=1..n} A010702(i)) - A010702(n+1). - Bruno Berselli, Mar 12 2012

LINKS

Table of n, a(n) for n=1..49.

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

FORMULA

a(n) = 7*n - a(n-1) - 10 with n > 1, a(1)=1. - Vincenzo Librandi, Aug 05 2010

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

a(n) = 7*n/2 - 13/4 - 3*(-1)^n/4.

G.f.: x*(1+2*x+4*x^2) / ( (1+x)*(x-1)^2 ). (End)

MATHEMATICA

With[{c=7 Range[0, 50]}, Sort[Join[c+1, c+3]]] (* or *) LinearRecurrence[ {1, 1, -1}, {1, 3, 8}, 100] (* Harvey P. Dale, May 29 2012 *)

CROSSREFS

Sequence in context: A003038 A184870 A073547 * A083246 A023492 A022801

Adjacent sequences:  A047353 A047354 A047355 * A047357 A047358 A047359

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified September 21 08:38 EDT 2020. Contains 337268 sequences. (Running on oeis4.)