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Search: id:A088556
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| A088556 |
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Numbers of the form (4^n + 4^(n-1) + ... + 1) + (n mod 2). |
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+0
1
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| 6, 21, 86, 341, 1366, 5461, 21846, 87381, 349526, 1398101, 5592406, 22369621, 89478486, 357913941, 1431655766, 5726623061, 22906492246, 91625968981, 366503875926, 1466015503701, 5864062014806, 23456248059221, 93824992236886
(list; graph; listen)
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OFFSET
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1,1
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FORMULA
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If n is even, then 4^n + ... + 1 = (4^(n+1) - 1)/3 = (2^(n+1) - 1)(2^n+1) + 1)/3. - R. K. Guy, Nov 17, 2003
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PROGRAM
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(PARI) trajpolypn(n1) = { for(x1=1, n1, y1 = polypn(4, x1); print1(y1", ") ) } polypn(n, p) = { x=n; if(p%2, y=2, y=1); for(m=1, p, y=y+x^m; ); return(y) }
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CROSSREFS
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Sequence in context: A053768 A108306 A134927 this_sequence A137966 A005498 A002222
Adjacent sequences: A088553 A088554 A088555 this_sequence A088557 A088558 A088559
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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 17 2003
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