A047602 Numbers that are congruent to {0, 1, 2, 3, 4, 5} mod 8.

0, 1, 2, 3, 4, 5, 8, 9, 10, 11, 12, 13, 16, 17, 18, 19, 20, 21, 24, 25, 26, 27, 28, 29, 32, 33, 34, 35, 36, 37, 40, 41, 42, 43, 44, 45, 48, 49, 50, 51, 52, 53, 56, 57, 58, 59, 60, 61, 64, 65, 66, 67, 68, 69, 72, 73, 74, 75, 76, 77, 80, 81, 82, 83, 84, 85, 88

Offset: 1

Author

N. J. A. Sloane

Keywords

• nonn
• easy

Links

• G. C. Greubel, Table of n, a(n) for n = 1..1000
• Index entries for linear recurrences with constant coefficients, signature (1,0,0,0,0,1,-1).

Crossrefs

Cf. A047420, A047549.

Programs

Magma

[n: n in [0..150] | n mod 8 in [0..5]]; // Vincenzo Librandi, May 04 2016

Maple

A047602:=n->floor((8/7)*floor(7*(n-1)/6)): seq(A047602(n), n=1..100); # Wesley Ivan Hurt, May 29 2016

Mathematica

Table[Floor[(8/7) Floor[7 (n - 1) / 6]], {n, 80}] (* Vincenzo Librandi, May 04 2016 *)
LinearRecurrence[{1, 0, 0, 0, 0, 1, -1}, {0, 1, 2, 3, 4, 5, 8}, 50] (* G. C. Greubel, May 29 2016 *)

Formula

a(n) = floor((8/7)*floor(7*(n-1)/6)). - Bruno Berselli, May 03 2016

From Chai Wah Wu, May 29 2016: (Start)

a(n) = a(n-1) + a(n-6) - a(n-7) for n>7.

G.f.: x^2*(3*x^5 + x^4 + x^3 + x^2 + x + 1)/(x^7 - x^6 - x + 1). (End)

From Wesley Ivan Hurt, Jun 15 2016: (Start)

a(n) = (24*n-39-3*cos(n*Pi)-4*sqrt(3)*cos((4*n+1)*Pi/6)-12*sin((1-2*n)*Pi/6))/18.

a(6k) = 8k-3, a(6k-1) = 8k-4, a(6k-2) = 8k-5, a(6k-3) = 8k-6, a(6k-4) = 8k-7, a(6k-5) = 8k-8. (End)

Sum_{n>=2} (-1)^n/a(n) = sqrt(2)*Pi/16 + 7*log(2)/8 + sqrt(2)*log(3-2*sqrt(2))/16. - Amiram Eldar, Dec 26 2021