A366785 Greatest common divisor of the number of prime factors (counted with multiplicity, A001222) and the greatest prime index (A061395) of n.

0, 1, 1, 1, 1, 2, 1, 1, 2, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 3, 2, 1, 1, 2, 1, 2, 1, 1, 1, 3, 1, 1, 1, 1, 2, 2, 1, 2, 2, 1, 1, 1, 1, 1, 3, 1, 1, 1, 2, 3, 1, 3, 1, 2, 1, 4, 2, 2, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 2, 3, 1, 1, 3, 1, 1, 2, 1, 1, 4, 1, 2, 2, 1, 1, 1, 2, 3, 1, 1, 2, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1

Offset

1,6

Links

Antti Karttunen, Table of n, a(n) for n = 1..65537

Index entries for sequences related to prime indices in the factorization of n

Formula

a(n) = gcd(A001222(n), A061395(n)).

For n >= 2, a(n) = A001222(n) / A360615(n) = A061395(n) / A360614(n).

Prog

(PARI)
A061395(n) = if(n>1, primepi(vecmax(factor(n)[, 1])), 0);
A366785(n) = gcd(bigomega(n), A061395(n));

Crossrefs

Cf. A001222, A061395, A340608 (positions of 1's), A360614, A360615.

Sequence in context: A276630 A176048 A359141 * A322480 A251683 A354579

Adjacent sequences: A366782 A366783 A366784 * A366786 A366787 A366788

Keyword

nonn

Author

Antti Karttunen, Oct 23 2023

Status

approved