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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 MATHEMATICA b[n_, i_] := b[n, i] = If[n <= i, 1, 0] + Sum[If[d <= i && Mod[d, 2]==0 && Mod[n/d, 2]==0, b[n/d, Min[d-1, i]], 0], {d, Divisors[n][[2 ;; -2]]}]; a[n_] := b[4n, 4n]; Array[a, 100] (* Jean-François Alcover, Nov 05 2020, after Alois P. Heinz *) 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 December 5 03:04 EST 2023. Contains 367567 sequences. (Running on oeis4.)