A381748 a(n) is the number of primes (counted with multiplicity) in row n of A051599.

1, 2, 2, 4, 2, 4, 2, 6, 2, 4, 4, 4, 4, 4, 2, 2, 2, 2, 2, 6, 2, 4, 2, 2, 2, 4, 4, 6, 2, 8, 6, 6, 2, 2, 2, 2, 4, 4, 2, 2, 2, 2, 4, 2, 2, 4, 2, 6, 2, 4, 4, 8, 2, 4, 4, 2, 2, 4, 4, 2, 2, 2, 2, 10, 2, 2, 4, 4, 2, 4, 2, 2, 2, 2, 2, 2, 4, 2, 4

Offset

0,2

Links

Vladimir Igorevich Lukyanchikov, Table of n, a(n) for n = 0..4999

Example

2;                                                    1 prime
3,  3;                                                2 primes
5,  6,   5;                                           2 primes
7,  11,  11,  7;                                      4 primes
11, 18,  22,  18,  11;                                2 primes

Prog

(Python)
from sympy import *
pr = list(primerange(2, 200))
lst = []
a = []
lst.append(1)
for i in range(1, 31):
    c = []
    c.append(pr[i])
    for j in range(1, i):
        c.append(a[j-1] + a[j])
    c.append(pr[i])
    count_primes = sum(isprime(x) for x in c)
    lst.append(count_primes)
    a = c
print(*lst)

Crossrefs

Cf. A051599.

Sequence in context: A372714 A147848 A306652 * A239614 A358216 A193432

Adjacent sequences: A381745 A381746 A381747 * A381749 A381750 A381751

Keyword

nonn

Author

Vladimir Igorevich Lukyanchikov, Mar 06 2025

Status

approved