A328829 Index of the least significant digit > 1 in the primorial base expansion of A276086(n), 0 if no such digit exists.

0, 0, 0, 0, 0, 3, 2, 2, 3, 0, 3, 4, 3, 3, 3, 4, 3, 5, 2, 2, 3, 4, 3, 4, 3, 3, 3, 4, 3, 4, 0, 3, 3, 3, 4, 4, 2, 2, 3, 0, 3, 5, 3, 3, 3, 5, 3, 5, 2, 2, 3, 5, 3, 5, 3, 3, 3, 5, 3, 6, 3, 4, 3, 3, 3, 3, 2, 2, 3, 5, 3, 5, 3, 3, 3, 5, 3, 5, 2, 2, 3, 5, 3, 5, 3, 3, 3, 5, 3, 5, 3, 3, 4, 3, 3, 3, 2, 2, 3, 5, 3, 5, 3, 3, 3, 5

Offset

0,6

Comments

a(n) = index of the least non-unitary prime divisor of A276087(n) or 0 if no such prime-divisor exists.

Links

Antti Karttunen, Table of n, a(n) for n = 0..65537

Index entries for sequences related to primorial base

Formula

a(n) = A328828(A276086(n)) = A277885(A276087(n)).

Prog

(PARI)
A276086(n) = { my(m=1, p=2); while(n, m *= (p^(n%p)); n = n\p; p = nextprime(1+p)); (m); };
A328828(n) = { my(i=1, p=2); while(n, if((n%p)>1, return(i)); i++; n = n\p; p = nextprime(1+p)); (0); };
A328829(n) = A328828(A276086(n));
(PARI)
A277885(n) = if(1==n, 0, my(f=factor(n)); for(i=1, #f~, if(f[i, 2]>1, return(primepi(f[i, 1])))); (0));
A328829(n) = A277885(A276086(A276086(n)));

Crossrefs

Cf. A276086, A276087, A277885, A328828, A328836 (positions of zeros).

Sequence in context: A065437 A097721 A073756 * A006379 A217956 A105198

Adjacent sequences: A328826 A328827 A328828 * A328830 A328831 A328832

Keyword

nonn

Author

Antti Karttunen, Oct 29 2019

Status

approved