A047438 - OEIS

A047438

Numbers that are congruent to {1, 5, 6} mod 8.

1, 5, 6, 9, 13, 14, 17, 21, 22, 25, 29, 30, 33, 37, 38, 41, 45, 46, 49, 53, 54, 57, 61, 62, 65, 69, 70, 73, 77, 78, 81, 85, 86, 89, 93, 94, 97, 101, 102, 105, 109, 110, 113, 117, 118, 121, 125, 126, 129, 133, 134, 137, 141, 142, 145, 149, 150, 153, 157, 158

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OFFSET

1,2

LINKS

Table of n, a(n) for n=1..60.

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

FORMULA

G.f.: x*(1+4*x+x^2+2*x^3)/((1+x+x^2)*(x-1)^2). - R. J. Mathar, Dec 07 2011

From Wesley Ivan Hurt, Jun 10 2016: (Start)

a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.

a(n) = 2*(12*n-6-3*cos(2*n*Pi/3)-2*sqrt(3)*sin(2*n*Pi/3))/9.

a(3k) = 8k-2, a(3k-1) = 8k-3, a(3k-2) = 8k-7. (End)