A141377 - OEIS

A141377

a(n) = the smallest positive integer non-coprime to both n and d(n), where d(n) is the number of divisors of n.

2, 6, 6, 10, 2, 14, 2, 3, 2, 22, 2, 26, 2, 6, 10, 34, 2, 38, 2, 6, 2, 46, 2, 15, 2, 6, 2, 58, 2, 62, 2, 6, 2, 10, 3, 74, 2, 6, 2, 82, 2, 86, 2, 3, 2, 94, 2, 21, 2, 6, 2, 106, 2, 10, 2, 6, 2, 118, 2, 122, 2, 3, 14, 10, 2, 134, 2, 6, 2, 142, 2, 146, 2, 3, 2, 14, 2, 158, 2, 15, 2, 166, 2, 10, 2, 6

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OFFSET

2,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 2..16385

FORMULA

a(n) = A141327(n, A000005(n)).

PROG

(PARI) A141377(n) = { my(d=numdiv(n)); for(k=2, oo, if(gcd(k, n)>1 && gcd(k, d)>1, return(k))); }; \\ Antti Karttunen, Feb 18 2023

CROSSREFS

Cf. A141327, A141378, A141379.

Sequence in context: A353624 A372610 A021978 * A006955 A306745 A196053