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A047584
Numbers that are congruent to {1, 3, 5, 6, 7} mod 8.
2
1, 3, 5, 6, 7, 9, 11, 13, 14, 15, 17, 19, 21, 22, 23, 25, 27, 29, 30, 31, 33, 35, 37, 38, 39, 41, 43, 45, 46, 47, 49, 51, 53, 54, 55, 57, 59, 61, 62, 63, 65, 67, 69, 70, 71, 73, 75, 77, 78, 79, 81, 83, 85, 86, 87, 89, 91, 93, 94, 95, 97, 99, 101, 102, 103, 105, 107
OFFSET
1,2
COMMENTS
Numbers n such that A232713(n) is divisible by n. [Bruno Berselli, Dec 11 2013]
FORMULA
G.f.: (1 + x)*(1 + x + x^2 + x^4) / ((1 - x)^2*(1 + x + x^2 + x^3 + x^4)). [Bruno Berselli, Dec 11 2013]
From Wesley Ivan Hurt, Dec 30 2016: (Start)
a(n) = a(n-1) + a(n-5) - a(n-6) for n > 6.
a(n) = (40n - 10 + 3*(n mod 5) + 3*((n+1) mod 5) - 2*((n+2) mod 5) - 2*((n+3) mod 5) - 2*((n+4) mod 5))/25. (End)
MATHEMATICA
Select[Range@ 107, Or[OddQ@ Mod[#, 8], Mod[#, 8] == 6] &] (* Michael De Vlieger, Oct 23 2015 *)
#+{1, 3, 5, 6, 7}&/@(8*Range[0, 20])//Flatten (* Harvey P. Dale, May 13 2019 *)
PROG
(PARI) x='x+O('x^100); Vec((1+x)*(1+x+x^2+x^4)/((1-x)^2*(1+x+x^2+x^3+ x^4))) \\ Altug Alkan, Oct 22 2015
CROSSREFS
Cf. A232713.
Sequence in context: A064802 A233570 A181766 * A229089 A277573 A328585
KEYWORD
nonn,easy
STATUS
approved