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Search: id:A071644
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A071644 a(n) = A005148(2^n-1)/8^(n-1). +0
1
1, 311, 433380445, 10478887384420274295559, 72383623935281195994580596438773770789899563140885, 39891231890836797259743675264050089835308134898303203181868683359843686746718703346865629969758112672725599 (list; graph; listen)
OFFSET

1,2

COMMENT

Appears to always be an integer. General conjecture: the numbers k such that 8^a is the highest power of 2 dividing A005148(k) is the same sequence as numbers k such that k has exactly (a+1) 1's in his binary representation. Hence this sequence gives the smallest integer of the form A005148(k) /8^(n-1).

PROGRAM

(PARI) for(s=1, 8, n=2^s-1; print1(polcoeff(prod(k=1, (n+1)\2, 1+x^(2*k-1), 1+x*O(x^n))^(24*n), n)/24/8^(s-1), ", "))

CROSSREFS

Adjacent sequences: A071641 A071642 A071643 this_sequence A071645 A071646 A071647

Sequence in context: A046495 A061329 A082862 this_sequence A139638 A112542 A011774

KEYWORD

easy,nonn

AUTHOR

Benoit Cloitre (benoit7848c(AT)orange.fr), Jun 22 2002

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Last modified October 10 20:39 EDT 2008. Contains 144831 sequences.


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