A355728 - OEIS

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A355728

Indices k of partition function where consecutive p(k) and p(k+1) are prime.

2, 3, 4, 5, 1085

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OFFSET

1,1

COMMENTS

Because asymptotically the size of the partition number function p(n) is ~ O(exp(sqrt(n))), and the probability of primality of p(n) is ~ O(1/sqrt(n)) and the combined probability of primality of p(n) and p(n+1) is ~ O(1/n), the sum of the prime probabilities is diverging and there are no obvious restrictions on primality; therefore, this sequence may be conjectured to be infinite.

a(6) > 10^8.

LINKS

Table of n, a(n) for n=1..5.

EXAMPLE

5 is in the sequence because A000041(5) = 7 and A000041(6) = 11 are prime.

PROG

(PARI) for(k=1, 5000, if(ispseudoprime(numbpart(k))&&ispseudoprime(numbpart(k+1)), print1(k, ", ")))

CROSSREFS

Cf. A000041, A046063, A072213, A284594, A285086, A285087, A285088, A355704, A355705, A355706.

Sequence in context: A037435 A001096 A004900 * A062937 A004911 A062934

Adjacent sequences: A355725 A355726 A355727 * A355729 A355730 A355731

KEYWORD

nonn,hard,more

AUTHOR

Serge Batalov, Jul 15 2022

STATUS

approved