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Search: id:A084615
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| A084615 |
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a(n) = sum of absolute values of coefficients of (1+x-3x^2)^n. |
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+0
16
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| 1, 5, 23, 99, 401, 1525, 6345, 27331, 122083, 520805, 2117293, 8301441, 34517395, 147850771, 628707981, 2675100397, 10920387779, 43701876543, 180872758207, 769658883325, 3243501133481, 13617178197183, 56148348498199
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OFFSET
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0,2
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PROGRAM
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(PARI) for(n=0, 40, S=0; for(k=0, 2*n, t=polcoeff((1+x-3*x^2)^n, k, x); S=S+abs(t)); print1(S", "))
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CROSSREFS
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Cf. A002426, A084600-A084614.
Sequence in context: A055489 A109765 A119012 this_sequence A049674 A077277 A073682
Adjacent sequences: A084612 A084613 A084614 this_sequence A084616 A084617 A084618
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KEYWORD
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nonn
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AUTHOR
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Paul D. Hanna (pauldhanna(AT)juno.com), Jun 01 2003
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