cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A047469 Numbers that are congruent to {0, 1, 2} mod 8.

Original entry on oeis.org

0, 1, 2, 8, 9, 10, 16, 17, 18, 24, 25, 26, 32, 33, 34, 40, 41, 42, 48, 49, 50, 56, 57, 58, 64, 65, 66, 72, 73, 74, 80, 81, 82, 88, 89, 90, 96, 97, 98, 104, 105, 106, 112, 113, 114, 120, 121, 122, 128, 129, 130, 136, 137, 138, 144, 145, 146, 152, 153, 154
Offset: 1

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Keywords

Crossrefs

Cf. A030341.
Cf. similar sequences with formula n+i*floor(n/3) listed in A281899.

Programs

  • Magma
    [n : n in [0..150] | n mod 8 in [0..2]]; // Wesley Ivan Hurt, Jun 09 2016
  • Maple
    A047469:=n->(24*n-39-15*cos(2*n*Pi/3)+5*sqrt(3)*sin(2*n*Pi/3))/9: seq(A047469(n), n=1..100); # Wesley Ivan Hurt, Jun 09 2016
  • Mathematica
    Select[Range[0, 150], MemberQ[{0, 1, 2}, Mod[#, 8]] &] (* Wesley Ivan Hurt, Jun 09 2016 *)
  • PARI
    a(n)=n+(n-1)\3*5-1
    

Formula

G.f.: x*(1 + x + 6*x^2)/((1 - x)*(1 - x^3)).
a(n+1) = Sum_{k>=0} A030341(n,k)*b(k) with b(0)=1 and b(k) = 8*3^(k-1) for k>0. - Philippe Deléham, Oct 24 2011
From Wesley Ivan Hurt, Jun 09 2016: (Start)
a(n) = a(n-1) + a(n-3) - a(n-4) for n>4.
a(n) = (24*n-39-15*cos(2*n*Pi/3)+5*sqrt(3)*sin(2*n*Pi/3))/9.
a(3k) = 8k-6, a(3k-1) = 8k-7, a(3k-2) = 8k-8. (End)
a(n) = n + 5*floor((n-1)/3) - 1. - Bruno Berselli, Feb 06 2017