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A336445 Integers m such that m/sopf(m) is a prime number where sopf(m) is A008472(m), the sum of the distinct primes dividing m. 2
4, 9, 25, 30, 49, 70, 84, 105, 121, 169, 231, 234, 260, 286, 289, 361, 456, 529, 532, 627, 646, 805, 841, 897, 961, 1116, 1364, 1369, 1581, 1665, 1681, 1798, 1849, 1924, 2064, 2150, 2209, 2632, 2809, 2967, 3055, 3339, 3481, 3526, 3721, 4489, 4543, 4824, 5025, 5041 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

All squares of primes (A001248) are terms.

LINKS

Michel Marcus, Table of n, a(n) for n = 1..1049 (terms up to 10^7)

EXAMPLE

4 is a term since sopf(4)=2 and 4/2 = 2 is a prime.

30 is a term since sopf(30)=10 and 30/10 = 3 is a prime.

PROG

(PARI) sopf(n)=vecsum(factor(n)[, 1]); \\ A008472

isokp(k) = my(q=k/sopf(k)); (denominator(q)==1) && isprime(q);

CROSSREFS

Cf. A008472 (sopf).

Subsequence of A071139.

A001248 is a subsequence.

Cf. A336296, A336297.

Sequence in context: A340640 A073045 A045967 * A232241 A163836 A175085

Adjacent sequences:  A336442 A336443 A336444 * A336446 A336447 A336448

KEYWORD

nonn

AUTHOR

Michel Marcus, Jul 22 2020

STATUS

approved

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Last modified May 19 16:50 EDT 2022. Contains 353847 sequences. (Running on oeis4.)