A255971 Number of terms in A255967 less than 10^n.

0, 1, 1, 1, 11, 168, 2356, 28321, 326831, 3678318, 39570252, 418509525

Offset: 0

Author

Arkadiusz Wesolowski, Mar 12 2015

Keywords

• nonn
• more

Crossrefs

Cf. A254248, A255816, A255967, A256164, A256238.

Programs

PARI

isA255967(m) = if(!(m % 2), 0, my(pow = 2); while(pow < m && !isprime(m - pow) && !isprime(m + pow), pow *= 2); pow > m);
list(len) = {my(pow = 10, c = 0); print1(0, ", "); for(k = 1, 10^len, if(isA255967(k), c++); if(k == pow-1, print1(c, ", "); pow *= 10));} \\ Amiram Eldar, Jul 19 2025

Extensions

a(9)-a(11) from Amiram Eldar, Jul 19 2025