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Search: id:A103730
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| 3, 17, 109, 203, 527, 773, 1473, 3163, 3929, 6947, 9639, 11213, 14857, 21683, 30333, 33659, 45077, 53969, 58823, 75113, 87493, 108503, 141407, 160099, 170033, 191117, 202283, 225903, 322937, 355029, 407047, 425453, 525843, 547649, 616667, 691253
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OFFSET
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0,1
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COMMENT
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The two a(n) formulae, given below, produce natural numbers for all n>=0.
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FORMULA
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a(n)=-A103728(n+3, 3)=-(1 -(p(n+3)-1)*binomial(p(n+3)-1, 3))/p(n+3), with p(n):=A000040(n) (n-th prime).
a(n)= -(17 - 17*p(n+3) + 7*p(n+3)^2 - p(n+3)^3)/3! = -sum(A103718(k, m)*p(n+3)^m, m=0..3)/3!.
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CROSSREFS
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Sequence in context: A074563 A077145 A123772 this_sequence A074556 A119259 A131204
Adjacent sequences: A103727 A103728 A103729 this_sequence A103731 A103732 A103733
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KEYWORD
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nonn,easy
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AUTHOR
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Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de), Feb 24 2005
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