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A047568
Numbers that are congruent to {1, 4, 5, 6, 7} mod 8.
1
1, 4, 5, 6, 7, 9, 12, 13, 14, 15, 17, 20, 21, 22, 23, 25, 28, 29, 30, 31, 33, 36, 37, 38, 39, 41, 44, 45, 46, 47, 49, 52, 53, 54, 55, 57, 60, 61, 62, 63, 65, 68, 69, 70, 71, 73, 76, 77, 78, 79, 81, 84, 85, 86, 87, 89, 92, 93, 94, 95, 97, 100, 101, 102, 103
OFFSET
1,2
FORMULA
From Chai Wah Wu, Jun 10 2016: (Start)
a(n) = a(n-1) + a(n-5) - a(n-6) for n > 6.
G.f.: x*(x^5 + x^4 + x^3 + x^2 + 3*x + 1)/(x^6 - x^5 - x + 1). (End)
From Wesley Ivan Hurt, Jul 27 2016: (Start)
a(n) = a(n-5) + 8 for n>5.
a(n) = (40*n - 5 + 3*(n mod 5) + 3*((n+1) mod 5) + 3*((n+2) mod 5) - 7*((n+3) mod 5) - 2*((n+4) mod 5))/25.
a(5k) = 8k-1, a(5k-1) = 8k-2, a(5k-2) = 8k-3, a(5k-3) = 8k-4, a(5k-4) = 8k-7. (End)
MAPLE
A047568:=n->8*floor(n/5)+[1, 4, 5, 6, 7][(n mod 5)+1]: seq(A047568(n), n=0..100); # Wesley Ivan Hurt, Jul 27 2016
MATHEMATICA
Select[Range[100], MemberQ[{1, 4, 5, 6, 7}, Mod[#, 8]]&] (* Harvey P. Dale, Nov 17 2013 *)
PROG
(Magma) [n : n in [0..150] | n mod 8 in [1, 4, 5, 6, 7]]; // Wesley Ivan Hurt, Jul 27 2016
CROSSREFS
Sequence in context: A010399 A215046 A008523 * A139453 A010391 A010419
KEYWORD
nonn,easy
STATUS
approved