A085643 - OEIS

A085643

Refines sequence A078812 using permutations and products of exponents on least prime signatures.

1, 2, 1, 3, 4, 1, 4, 6, 4, 6, 1, 5, 8, 12, 9, 12, 8, 1, 6, 10, 16, 9, 12, 36, 8, 12, 24, 10, 1, 7, 12, 20, 24, 15, 48, 36, 27, 16, 72, 32, 15, 40, 12, 1, 8, 14, 24, 30, 16, 18, 60, 48, 72, 54, 20, 96, 144, 54, 16, 20, 120, 80, 18, 60, 14, 1

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OFFSET

1,2

COMMENTS

The shape sequence for this table is A000041. Row sums in the example are A000079, A006906 and A001906.

LINKS

Table of n, a(n) for n=1..66.

EXAMPLE

When the signatures (A025487) are listed in A036035 order the number of permutations of the exponents begin

1, 1 1, 1 2 1, 1 2 1 3 1, 1 2 2 3 3 4 1, ... b(n) and the products begin

1, 2 1, 3 2 1, 4 3 4 2 1, 5 4 6 3 4 2 1, ... c(n) thus we can write

1, 2 1, 3 4 1, 4 6 4 6 1, 5 8 12 9 12 8 1, ... a(n) = b(n)*c(n)

CROSSREFS

Cf. A078812.

Sequence in context: A104471 A174828 A305309 * A174829 A132110 A039912

Adjacent sequences: A085640 A085641 A085642 * A085644 A085645 A085646

KEYWORD

nonn,tabf

AUTHOR

Alford Arnold, Aug 15 2003

STATUS

approved