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A108502 Number of factorizations of 4*n into distinct even numbers. 3
1, 2, 2, 2, 2, 3, 2, 3, 2, 3, 2, 5, 2, 3, 3, 4, 2, 4, 2, 5, 3, 3, 2, 7, 2, 3, 3, 5, 2, 6, 2, 5, 3, 3, 3, 7, 2, 3, 3, 7, 2, 6, 2, 5, 4, 3, 2, 10, 2, 4, 3, 5, 2, 6, 3, 7, 3, 3, 2, 11, 2, 3, 4, 6, 3, 6, 2, 5, 3, 6, 2, 11, 2, 3, 4, 5, 3, 6, 2, 10, 3, 3, 2, 11, 3, 3, 3, 7, 2, 9, 3, 5, 3, 3, 3, 14, 2, 4, 4, 7, 2, 6 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

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

EXAMPLE

a(15)=3 because 15*4=60 can be factored as 60=30*2=10*6.

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-1, 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. A045778, A108501, A108503.

Sequence in context: A010553 A262095 A163374 * A260235 A078120 A057525

Adjacent sequences:  A108499 A108500 A108501 * A108503 A108504 A108505

KEYWORD

nonn

AUTHOR

Christian G. Bower, Jun 06 2005

STATUS

approved

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Last modified November 11 18:50 EST 2019. Contains 329031 sequences. (Running on oeis4.)