login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A047486
Numbers that are congruent to {0, 1, 3, 5, 7} mod 8.
6
0, 1, 3, 5, 7, 8, 9, 11, 13, 15, 16, 17, 19, 21, 23, 24, 25, 27, 29, 31, 32, 33, 35, 37, 39, 40, 41, 43, 45, 47, 48, 49, 51, 53, 55, 56, 57, 59, 61, 63, 64, 65, 67, 69, 71, 72, 73, 75, 77, 79, 80, 81, 83, 85, 87, 88, 89
OFFSET
1,3
COMMENTS
Also nonnegative integers primitively represented by x^2 - y^2. - Ray Chandler, Aug 23 2014
LINKS
N. J. A. Sloane et al., Binary Quadratic Forms and OEIS (Index to related sequences, programs, references)
FORMULA
G.f.: x^2*(x^2 + 1)*(1 + x)^2/((x^4 + x^3 + x^2 + x + 1)*(x - 1)^2). - R. J. Mathar, Oct 07 2011
From Wesley Ivan Hurt, Dec 28 2016: (Start)
a(n) = a(n-1) + a(n-5) - a(n-6) for n > 6.
a(n) = (40*n - 40 - 2*(n mod 5) - 2*((n+1) mod 5) - 2*((n+2) mod 5) + 3*((n+3) mod 5) + 3*((n+4) mod 5))/25. (End)
CROSSREFS
Sequence in context: A295075 A184996 A153309 * A229838 A191257 A120212
KEYWORD
nonn,easy
STATUS
approved