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A108501 Number of factorizations of 4*n into even numbers. 3
2, 3, 2, 5, 2, 4, 2, 7, 3, 4, 2, 7, 2, 4, 3, 11, 2, 6, 2, 7, 3, 4, 2, 12, 3, 4, 3, 7, 2, 7, 2, 15, 3, 4, 3, 12, 2, 4, 3, 12, 2, 7, 2, 7, 4, 4, 2, 19, 3, 6, 3, 7, 2, 8, 3, 12, 3, 4, 2, 14, 2, 4, 4, 22, 3, 7, 2, 7, 3, 7, 2, 21, 2, 4, 4, 7, 3, 7, 2, 19, 4, 4, 2, 14, 3, 4, 3, 12, 2, 11, 3, 7, 3, 4, 3, 30, 2 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..10000

EXAMPLE

a(6)=4 because 6*4=24 can be factored as 24=12*2=6*4=6*2*2.

MAPLE

with(numtheory):

b:= proc(n, i) option remember; `if`(n<=i, 1, 0)+

      add(`if`(d<=i and irem(d, 2)=0 and irem(n/d, 2)=0,

      b(n/d, min(d, i)), 0), d=divisors(n) minus {1, n})

    end:

a:= n-> b(4*n$2):

seq(a(n), n=1..100);  # Alois P. Heinz, Feb 17 2015

CROSSREFS

Cf. A001055, A108502, A108503.

Sequence in context: A000705 A073751 A258581 * A166226 A263978 A263726

Adjacent sequences:  A108498 A108499 A108500 * A108502 A108503 A108504

KEYWORD

nonn

AUTHOR

Christian G. Bower, Jun 06 2005

STATUS

approved

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Last modified December 9 17:46 EST 2016. Contains 278985 sequences.