A373833 - OEIS

A373833

a(n) = gcd(n, A276150(n)), where A276150 is the digit sum in the primorial base.

0, 1, 1, 1, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 1, 1, 4, 1, 3, 1, 4, 1, 1, 1, 4, 5, 1, 3, 2, 1, 1, 1, 2, 3, 1, 1, 2, 1, 1, 1, 4, 1, 3, 1, 4, 5, 1, 1, 4, 1, 5, 3, 2, 1, 1, 1, 2, 1, 1, 1, 2, 1, 1, 1, 4, 5, 3, 1, 4, 1, 5, 1, 4, 1, 1, 3, 2, 7, 1, 1, 2, 1, 1, 1, 6, 1, 1, 1, 8, 1, 3, 1, 4, 1, 1, 1, 4, 1, 1, 3, 2, 1, 1, 1, 2, 7

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OFFSET

0,5

LINKS

Antti Karttunen, Table of n, a(n) for n = 0..100000

Index entries for sequences related to primorial base

FORMULA

a(n) = A373835(A276086(n)).

For n >= 1, a(n) = gcd(A276150(n), A373832(n)).

PROG

(PARI)

A276150(n) = { my(s=0, p=2, d); while(n, d = (n%p); s += d; n = (n-d)/p; p = nextprime(1+p)); (s); };