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A047274 Numbers that are congruent to {0, 1} mod 7. 7
0, 1, 7, 8, 14, 15, 21, 22, 28, 29, 35, 36, 42, 43, 49, 50, 56, 57, 63, 64, 70, 71, 77, 78, 84, 85, 91, 92, 98, 99, 105, 106, 112, 113, 119, 120, 126, 127, 133, 134, 140, 141, 147, 148, 154, 155, 161, 162, 168, 169 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Nonnegative k such that k or 6*k + 1 is divisible by 7. - Bruno Berselli, Feb 13 2018
LINKS
FORMULA
a(n) = 7*n - a(n-1) - 13 for n>1, a(1)=0. - Vincenzo Librandi, Aug 05 2010
From R. J. Mathar, Oct 08 2011: (Start)
a(n) = 7*n/2 - 19/4 - 5*(-1)^n/4.
G.f.: x^2*(1 + 6*x) / ((1 + x)*(x - 1)^2). (End)
a(n+1) = Sum_{k>=0} A030308(n,k)*A135092(k). - Philippe Deléham, Oct 17 2011
E.g.f.: 6 + ((14*x - 19)*exp(x) - 5*exp(-x))/4. - David Lovler, Aug 31 2022
PROG
(PARI) forstep(n=0, 200, [1, 6], print1(n", ")) \\ Charles R Greathouse IV, Oct 17 2011
CROSSREFS
Sequence in context: A286261 A136037 A085334 * A037368 A281710 A037970
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified April 15 14:37 EDT 2024. Contains 371689 sequences. (Running on oeis4.)