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Search: id:A088581
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| A088581 |
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Numbers of the form n*x^n + (n-1)*x^(n-1) + . . . + x + 1 for x=3. |
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+0
1
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| 1, 4, 22, 103, 427, 1642, 6016, 21325, 73813, 250960, 841450, 2790067, 9167359, 29893558, 96855124, 312088729, 1000836265, 3196219036, 10169787838, 32252755711, 101988443731, 321655860994, 1012039172392, 3177332285413
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Sum of reciprocals = 1.308346570619799777189561356..
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FORMULA
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1/4 * [(6n-3)3^n + 7].
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EXAMPLE
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3*3^3 + 2*3^2 + 3 + 1 = 103
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PROGRAM
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(PARI) trajpolypn(n1, k) = { s=0; for(x1=0, n1, y1 = polypn2(k, x1); print1(y1", "); s+=1.0/y1; ); print(); print(s) } polypn2(n, p) = { x=n; y=1; for(m=1, p, y=y+m*x^m; ); return(y) }
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CROSSREFS
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Sequence in context: A036926 A079272 A007901 this_sequence A017970 A099013 A001436
Adjacent sequences: A088578 A088579 A088580 this_sequence A088582 A088583 A088584
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KEYWORD
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nonn
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AUTHOR
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Cino Hilliard (hillcino368(AT)gmail.com), Nov 20 2003
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