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Search: id:A134965
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| A134965 |
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a(0)=3; for n>0, a(n)=a(n-1)+7+2*mod(n,2). |
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+0
1
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| 3, 12, 19, 28, 35, 44, 51, 60, 67, 76, 83, 92, 99, 108, 115, 124, 131, 140
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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Starting weights for pyramid game; numbers n such that the equation m(m + 1)/2 + 1 - n == 0 mod m has a solution.
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FORMULA
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f[n_] = (1/2) (-1+ Sqrt[ -7 + 8 n]); a(n) = If[ IntegerQ[2*Sqrt[ -7 + 8*n]] && Mod[n - 7, 8] == 0, f(n)]
O.g.f.: (3+9*x+4*x^2)/[(-1+x)^2*(x+1)] . a(n)-a(n-1)= A010729(n) . - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Feb 05 2008
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MATHEMATICA
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Flatten[Table[If[ IntegerQ[2*Sqrt[ -7 + 8*n]] && Mod[n - 7, 8] == 0, f[n], {}], {n, 1, 10000}]]
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CROSSREFS
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Adjacent sequences: A134962 A134963 A134964 this_sequence A134966 A134967 A134968
Sequence in context: A052637 A120623 A043877 this_sequence A117554 A049714 A063244
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KEYWORD
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nonn
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AUTHOR
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Roger Bagula (rlbagulatftn(AT)yahoo.com), Jan 31 2008
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