A047256 - OEIS

A047256

Numbers that are congruent to {0, 1, 2, 3, 5} mod 6.

0, 1, 2, 3, 5, 6, 7, 8, 9, 11, 12, 13, 14, 15, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39, 41, 42, 43, 44, 45, 47, 48, 49, 50, 51, 53, 54, 55, 56, 57, 59, 60, 61, 62, 63, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 77, 78, 79

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OFFSET

1,3

LINKS

Table of n, a(n) for n=1..67.

Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,1,-1).

FORMULA

G.f.: x^2*(1+x)*(x^3 + x^2 + 1) / ( (x^4 + x^3 + x^2 + x + 1)*(x-1)^2 ). - R. J. Mathar, Oct 08 2011

Sum_{n>=2} (-1)^n/a(n) = (3-2*sqrt(3))*Pi/36 + log(2+sqrt(3))/sqrt(3). - Amiram Eldar, Dec 17 2021

a(n) = n + floor(n/5) - 1. - Aaron J Grech, Oct 03 2024

MATHEMATICA

Flatten[# + {0, 1, 2, 3, 5} & /@ (6 Range[0, 11])] (* or *)

Select[Range[0, 67], MemberQ[{0, 1, 2, 3, 5}, Mod[#, 6]] &] (* Robert G. Wilson v, Sep 26 2016 *)

LinearRecurrence[{1, 0, 0, 0, 1, -1}, {0, 1, 2, 3, 5, 6}, 60] (* Harvey P. Dale, Jul 20 2020 *)

CROSSREFS

Cf. A047226.

Sequence in context: A183570 A181092 A184526 * A039252 A332484 A360556

Adjacent sequences: A047253 A047254 A047255 * A047257 A047258 A047259

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane

STATUS

approved