Voozh

A389910

a(n) = min(n, A389909(n)).

1, 1, 3, 3, 5, 5, 7, 8, 8, 7, 11, 12, 13, 11, 12, 16, 17, 18, 19, 20, 20, 13, 23, 24, 18, 17, 16, 28, 29, 30, 31, 32, 28, 19, 30, 36, 37, 23, 39, 40, 41, 42, 43, 39, 24, 29, 47, 48, 49, 49, 51, 51, 53, 54, 42, 56, 57, 31, 59, 60, 61, 37, 40, 64, 65, 65, 67, 57, 69, 70, 71, 72, 73, 41, 36, 69, 70, 78, 79, 80, 32

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OFFSET

1,3

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

Index entries for sequences related to prime indices in the factorization of n.

FORMULA

a(n) = a(A003961(A252463(n))) = a(2*A252463(n)).

For all n >= 1, A252463(n) = A252463(a(n)).

PROG

(PARI)

A003961(n) = { my(f=factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };