A047436 - OEIS

A047436

Numbers that are congruent to {5, 6} mod 8.

5, 6, 13, 14, 21, 22, 29, 30, 37, 38, 45, 46, 53, 54, 61, 62, 69, 70, 77, 78, 85, 86, 93, 94, 101, 102, 109, 110, 117, 118, 125, 126, 133, 134, 141, 142, 149, 150, 157, 158, 165, 166, 173, 174, 181, 182, 189, 190

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..48.

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

FORMULA

From Vincenzo Librandi, Aug 06 2010: (Start)

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

a(n) = 8*n - a(n-1) - 5, n > 1. (End)

G.f. x*(5+x+2*x^2) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Dec 07 2011

Sum_{n>=1} (-1)^(n+1)/a(n) = (2-sqrt(2))*Pi/16 + log(2)/8 - sqrt(2)*log(sqrt(2)+1)/8. - Amiram Eldar, Dec 19 2021

MATHEMATICA

Select[Range[200], MemberQ[{5, 6}, Mod[#, 8]] &] (* Amiram Eldar, Dec 19 2021 *)

CROSSREFS

Union of A004770 and A017137.

Sequence in context: A051572 A344221 A348155 * A334320 A061437 A067245

Adjacent sequences: A047433 A047434 A047435 * A047437 A047438 A047439

KEYWORD

nonn

AUTHOR

N. J. A. Sloane

STATUS

approved