A244986 - OEIS

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

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OFFSET

0,3

LINKS

Table of n, a(n) for n=0..30.

FORMULA

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

EXAMPLE

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