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A047283
Numbers that are congruent to {0, 1, 3, 6} mod 7.
2
0, 1, 3, 6, 7, 8, 10, 13, 14, 15, 17, 20, 21, 22, 24, 27, 28, 29, 31, 34, 35, 36, 38, 41, 42, 43, 45, 48, 49, 50, 52, 55, 56, 57, 59, 62, 63, 64, 66, 69, 70, 71, 73, 76, 77, 78, 80, 83, 84, 85, 87, 90, 91, 92, 94, 97, 98, 99, 101, 104, 105, 106, 108, 111
OFFSET
1,3
FORMULA
G.f.: x^2*(1+2*x+3*x^2+x^3) / ( (1+x)*(x^2+1)*(x-1)^2 ). - R. J. Mathar, Oct 25 2011
a(n) = a(n-1) + a(n-4) - a(n-5) for n>5. - Harvey P. Dale, Mar 09 2012
From Wesley Ivan Hurt, May 22 2016: (Start)
a(n) = (14n-15+i^(2n)+(3+i)*i^(-n)+(3-i)*i^n)/8 where i=sqrt(-1).
a(2n) = A047336(n), a(2n-1) = A047355(n). (End)
MAPLE
A047283:=n->(14*n-15+I^(2*n)+(3+I)*I^(-n)+(3-I)*I^n)/8: seq(A047283(n), n=1..100); # Wesley Ivan Hurt, May 22 2016
MATHEMATICA
Select[Range[0, 100], MemberQ[{0, 1, 3, 6}, Mod[#, 7]]&] (* or *) LinearRecurrence[{1, 0, 0, 1, -1}, {0, 1, 3, 6, 7}, 60] (* Harvey P. Dale, Mar 09 2012 *)
PROG
(Magma) [n : n in [0..150] | n mod 7 in [0, 1, 3, 6]]; // Wesley Ivan Hurt, May 22 2016
CROSSREFS
Sequence in context: A050244 A295566 A266986 * A155932 A374483 A298980
KEYWORD
nonn,easy
EXTENSIONS
More terms from Wesley Ivan Hurt, May 22 2016
STATUS
approved