A342668 Largest prime in the denominator of ratio A341528(n)/A341529(n) (when presented in its lowest terms).

1, 3, 5, 7, 7, 5, 11, 3, 13, 7, 13, 7, 17, 11, 7, 31, 19, 13, 23, 7, 11, 13, 29, 5, 31, 17, 5, 11, 31, 7, 37, 3, 13, 19, 11, 7, 41, 23, 17, 7, 43, 11, 47, 3, 13, 29, 53, 31, 11, 31, 19, 17, 59, 5, 13, 11, 23, 31, 61, 7, 67, 37, 13, 127, 17, 13, 71, 19, 29, 11, 73, 13, 79, 41, 31, 23, 13, 17, 83, 31, 11, 43, 89, 11

Offset

1,2

Links

Table of n, a(n) for n=1..84.

Index entries for sequences computed from indices in prime factorization

Index entries for sequences related to sigma(n)

Formula

a(n) = A006530(A341527(n)).

Prog

(PARI)
A003961(n) = { my(f = factor(n)); for (i=1, #f~, f[i, 1] = nextprime(f[i, 1]+1)); factorback(f); };
A006530(n) = if(n>1, vecmax(factor(n)[, 1]), 1);
A341527(n) = { my(s=A003961(n)); denominator((sigma(s)*n)/(sigma(n)*s)); };
A342668(n) = A006530(A341527(n));

Crossrefs

Cf. A000203, A003961, A006530, A341527, A341528, A341529, A342667.

Cf. A341628 (same sequence applied onto prime shift array A246278).

Sequence in context: A361120 A092257 A316189 * A297346 A342622 A211517

Adjacent sequences: A342665 A342666 A342667 * A342669 A342670 A342671

Keyword

nonn

Author

Antti Karttunen, Mar 24 2021

Status

approved