A244986 a(n) = Position of 2^n among the numbers which are divisible by the square of their highest noncomposite factor (i.e., the union of {1} and A070003), 0 if not there.

1, 0, 2, 3, 5, 9, 14, 23, 37, 58, 90, 143, 225, 355, 563, 894, 1426, 2277, 3643, 5839, 9398, 15155, 24518, 39758, 64607, 105250, 171874, 281237, 461255, 758040, 1248270

Offset: 0

Author

Antti Karttunen, Jul 21 2014

Keywords

• nonn

Examples

			2 is not divisible by 2^2, thus a(2) = 0, the only zero in the sequence.
2^4 = 16 is the fifth term in [1, 4, 8, 9, 16, 18, 25, 27, 32, 36, ...] (the union of {1} and A070003), thus a(4) = 5.
2^5 = 32 is the ninth term in the same list, thus a(5) = 9.
		

Crossrefs

From a(2) onward one more than A244985.

Cf. A000079, A070003, A006254, A244984.

Formula

For all n >= 1, a(n+1) = A244984(A006254(n)).