A047248 Numbers that are congruent to {0, 2, 3, 4, 5} (mod 6).

0, 2, 3, 4, 5, 6, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 20, 21, 22, 23, 24, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 38, 39, 40, 41, 42, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 62, 63, 64, 65, 66, 68

Offset

1,2

Links

G. C. Greubel, Table of n, a(n) for n = 1..5000

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

Formula

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

Sum_{n>=2} (-1)^n/a(n) = log(2+sqrt(3))/(2*sqrt(3)) + log(2)/6 - (9-4*sqrt(3))*Pi/36. - Amiram Eldar, Dec 17 2021

Mathematica

Rest[CoefficientList[Series[x^2*(2 + x + x^2 + x^3 + x^4)/((x^4 + x^3 + x^2 + x + 1)*(x - 1)^2), {x, 0, 50}], x]] (* G. C. Greubel, Nov 02 2017 *)
DeleteCases[Range[0, 70], _?(Mod[#, 6]==1&)] (* or *) Complement[ Range[ 0, 70], Range[1, 70, 6]] (* Harvey P. Dale, Dec 30 2017 *)

Prog

(PARI) x='x+O('x^50); concat([0], Vec(x^2*(2+x+x^2+x^3+x^4)/((x^4 +x^3 +x^2 +x+1)*(x-1)^2))) \\ G. C. Greubel, Nov 02 2017

Crossrefs

Cf. A047252.

Sequence in context: A032798 A195122 A184520 * A114024 A030173 A048265

Adjacent sequences: A047245 A047246 A047247 * A047249 A047250 A047251

Keyword

nonn

Author

N. J. A. Sloane

Status

approved