This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A381748 #18 Mar 16 2025 21:37:08 %S A381748 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, %T A381748 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, %U A381748 2,4,2,2,2,2,2,2,4,2,4 %N A381748 a(n) is the number of primes (counted with multiplicity) in row n of A051599. %H A381748 Vladimir Igorevich Lukyanchikov, <a href="/A381748/b381748.txt">Table of n, a(n) for n = 1..5000</a> %e A381748 2; 1 prime %e A381748 3, 3; 2 primes %e A381748 5, 6, 5; 2 primes %e A381748 7, 11, 11, 7; 4 primes %e A381748 11, 18, 22, 18, 11; 2 primes %o A381748 (Python) %o A381748 from sympy import * %o A381748 pr = list(primerange(2, 200)) %o A381748 lst = [] %o A381748 a = [] %o A381748 lst.append(1) %o A381748 for i in range(1, 31): %o A381748 c = [] %o A381748 c.append(pr[i]) %o A381748 for j in range(1, i): %o A381748 c.append(a[j-1] + a[j]) %o A381748 c.append(pr[i]) %o A381748 count_primes = sum(isprime(x) for x in c) %o A381748 lst.append(count_primes) %o A381748 a = c %o A381748 print(*lst) %Y A381748 Cf. A051599. %K A381748 nonn %O A381748 0,2 %A A381748 _Vladimir Igorevich Lukyanchikov_, Mar 06 2025