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A331876 revision #3

A331876

Number of primes of the form P(k)=k^2 + k + 41 for k <= 10^n, where P(k) is Euler's prime-generating polynomial A202018.

4

2, 11, 87, 582, 4149, 31985, 261081, 2208197, 19132653

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OFFSET

0,1

LINKS

Table of n, a(n) for n=0..8.

EXAMPLE

a(0) = 2 because 41 and 43 are 2 primes generated for k <= 1 = 10^0.

a(1) = 11 because 41, 43, 47, 53, 61, 71, 83, 97, 113, 131, 151 are the 11 primes generated for k <= 10^1. (A202018(10)=151).

a(3) = 87 because 87 terms of A202018(0..100) are prime.

PROG

(PARI) n=0; m=1; for(k=0, 10^8, my(j=k^2+k+41); if(isprime(j), n++); if(k>=m, m=m*10; print1(n, ", ")))

CROSSREFS

Cf. A005846, A202018.

Sequence in context: A370475 A153304 A240998 * * A305537 A036076

Adjacent sequences: A331873 A331874 A331875 * A331877 A331878 A331879

KEYWORD

nonn,more

AUTHOR

Hugo Pfoertner, Jan 30 2020

STATUS

editing