A355442 a(n) = gcd(A003961(n), A276086(n)), where A003961 is fully multiplicative with a(p) = nextprime(p), and A276086 is primorial base exp-function.

1, 3, 1, 9, 1, 5, 1, 3, 5, 3, 1, 5, 1, 3, 5, 9, 1, 25, 1, 3, 5, 3, 1, 5, 1, 3, 125, 9, 1, 7, 1, 3, 1, 3, 7, 5, 1, 3, 5, 63, 1, 5, 1, 3, 175, 3, 1, 5, 1, 21, 5, 9, 1, 125, 7, 3, 5, 3, 1, 7, 1, 3, 1, 9, 7, 5, 1, 3, 5, 21, 1, 25, 1, 3, 245, 9, 1, 5, 1, 21, 125, 3, 1, 5, 7, 3, 5, 9, 1, 7, 1, 3, 1, 3, 7, 5, 1, 3, 5, 441

Offset

1,2

Links

Antti Karttunen, Table of n, a(n) for n = 1..11550

Antti Karttunen, Data supplement: n, a(n) computed for n = 1..65537

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to primorial base

Formula

a(n) = gcd(A003961(n), A276086(n)).

Prog

(PARI)
A003961(n) = { my(f = factor(n)); for(i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A355442(n) = gcd(A003961(n), A276086(n));

Crossrefs

Cf. A003961, A020639, A276086, A355001 [smallest prime factor of a(n)], A355456 [= gcd(sigma(n), a(n))], A355692 (Dirichlet inverse), A355820, A355821 (positions of 1's).

Cf. also A322361, A324198, A351459.

Sequence in context: A280192 A325375 A317202 * A331732 A197259 A200006

Adjacent sequences: A355439 A355440 A355441 * A355443 A355444 A355445

Keyword

nonn

Author

Antti Karttunen, Jul 13 2022

Status

approved