A181816 a(n) is the smallest integer that, upon multiplying any divisor of A025487(n), produces a member of A025487.

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

Author

Matthew Vandermast, Nov 30 2010

Keywords

• nonn

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).

Examples

			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.
		

Links

• Amiram Eldar, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A000265, A025487, A181811, A181817, A181818.

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).