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A181816
a(n) is the smallest integer that, upon multiplying any divisor of A025487(n), produces a member of A025487.
4
1, 1, 1, 2, 1, 2, 1, 2, 12, 1, 4, 2, 12, 1, 4, 2, 12, 1, 4, 24, 2, 360, 8, 12, 1, 4, 24, 2, 360, 8, 12, 1, 4, 24, 2, 360, 8, 144, 12, 1, 48, 4, 720, 16, 24, 2, 360, 8, 144, 12, 1
OFFSET
1,4
COMMENTS
All terms also belong to A181818. Each member of A181818 appears infinitely often. a(A025487(m)) = a(A025487(n)) iff A025487(m) and A025487(n) have the same odd part (cf. A000265).
LINKS
FORMULA
If A025487(n) = Product p(i)^e(i), then a(n) = Product A002110(i-1)^e(i); i.e., a(n) = A181811(A025487(n)).
a(n) = A181817(n)/A025487(n).
EXAMPLE
For any divisor d of 6 (d = 1, 2, 3, 6), 2*d (2, 4, 6, 12) is always a member of A025487. 2 is the smallest number with this relationship to 6; therefore, since 6 = A025487(4), a(4) = 2.
CROSSREFS
KEYWORD
nonn
AUTHOR
Matthew Vandermast, Nov 30 2010
STATUS
approved