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A047345
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Numbers that are congruent to {0, 4} mod 7.
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2
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0, 4, 7, 11, 14, 18, 21, 25, 28, 32, 35, 39, 42, 46, 49, 53, 56, 60, 63, 67, 70, 74, 77, 81, 84, 88, 91, 95, 98, 102, 105, 109, 112, 116, 119, 123, 126, 130, 133, 137, 140, 144, 147, 151, 154, 158, 161, 165, 168, 172, 175, 179, 182, 186, 189, 193
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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LINKS
| Index to sequences with linear recurrences with constant coefficients, signature (1,1,-1).
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FORMULA
| a(n) = ceiling(7*n/2).
a(n)=7*n-a(n-1)-10 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 05 2010]
a(n)=7*n/2-13/4+(-1)^n/4. G.f. x^2*(4+3*x) / ( (1+x)*(x-1)^2 ). - R. J. Mathar, Oct 08 2011
a(n+1)=Sum_k>=0 {A030308(n,k)*b(k)} with b(0)=4 and b(k)=A005009(k-1)=7*2^(k-1) for k>0. - From DELEHAM Philippe, Oct 17 2011.
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PROG
| (PARI) forstep(n=0, 200, [4, 3], print1(n", ")) \\ Charles R Greathouse IV, Oct 17 2011
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CROSSREFS
| Cf. A030123.
Sequence in context: A190769 A083051 A198269 * A087070 A198271 A161886
Adjacent sequences: A047342 A047343 A047344 * A047346 A047347 A047348
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KEYWORD
| nonn,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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