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Search: id:A091983
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| A091983 |
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a(0) = 1, a(n) = 20*sigma[3](n). |
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+0
1
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| 1, 20, 180, 560, 1460, 2520, 5040, 6880, 11700, 15140, 22680, 26640, 40880, 43960, 61920, 70560, 93620, 98280, 136260, 137200, 183960, 192640, 239760, 243360, 327600, 315020, 395640, 408800, 502240, 487800, 635040, 595840, 748980, 745920
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OFFSET
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0,2
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COMMENT
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G.f. A(x) satisfies 0=f(A(x),A(x^2),A(x^4)) where f(u,v,w)=u^2+33v^2+256w^2-18uv+16uw-288vw+220(v-w). - Michael Somos, Jul 19 2004
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PROGRAM
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(PARI) a(n)=if(n<1, n==0, 20*sigma(n, 3)) /* Michael Somos, Jul 19 2004 */
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CROSSREFS
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Adjacent sequences: A091980 A091981 A091982 this_sequence A091984 A091985 A091986
Sequence in context: A163689 A140044 A027332 this_sequence A037250 A000144 A047645
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com), following a suggestion of John McKay, Mar 19 2004
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