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A047307
Numbers that are congruent to {3, 4, 5, 6} mod 7.
1
3, 4, 5, 6, 10, 11, 12, 13, 17, 18, 19, 20, 24, 25, 26, 27, 31, 32, 33, 34, 38, 39, 40, 41, 45, 46, 47, 48, 52, 53, 54, 55, 59, 60, 61, 62, 66, 67, 68, 69, 73, 74, 75, 76, 80, 81, 82, 83, 87, 88, 89, 90, 94, 95, 96, 97, 101, 102, 103, 104, 108, 109, 110, 111
OFFSET
1,1
FORMULA
G.f.: x*(3+x+x^2+x^3+x^4) / ( (1+x)*(1+x^2)*(x-1)^2 ). - R. J. Mathar, Oct 25 2011
From Wesley Ivan Hurt, Jun 02 2016: (Start)
a(n) = a(n-1) + a(n-4) - a(n-5) for n>5.
a(n) = (14*n+1-3*i^(2*n)-(3-3*i)*i^(-n)-(3+3*i)*i^n)/8 where i=sqrt(-1).
a(2k) = A047288(k), a(2k-1) = A047389(k). (End)
MAPLE
A047307:=n->(14*n+1-3*I^(2*n)-(3-3*I)*I^(-n)-(3+3*I)*I^n)/8: seq(A047307(n), n=1..100); # Wesley Ivan Hurt, Jun 02 2016
MATHEMATICA
Table[(14n+1-3*I^(2*n)-(3-3*I)*I^(-n)-(3+3*I)*I^n)/8, {n, 80}] (* Wesley Ivan Hurt, Jun 02 2016 *)
PROG
(Magma) [n : n in [0..150] | n mod 7 in [3, 4, 5, 6]]; // Wesley Ivan Hurt, Jun 02 2016
CROSSREFS
Sequence in context: A353568 A364146 A059877 * A179774 A138918 A071186
KEYWORD
nonn,easy
STATUS
approved