A338976 Primes p such that p*A007953(p)+1 is prime.

2, 11, 13, 17, 19, 59, 71, 97, 107, 109, 149, 167, 181, 239, 271, 419, 431, 499, 509, 523, 547, 563, 613, 631, 691, 727, 811, 853, 859, 983, 1009, 1063, 1087, 1117, 1151, 1193, 1229, 1409, 1427, 1487, 1559, 1579, 1601, 1759, 1823, 1913, 1973, 2039, 2099, 2161, 2237, 2251, 2309, 2411, 2437, 2473

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(3) = 13 is a term because 13 and 13*(1+3)+1 = 53 are prime.

Maple

select(t -> isprime(t) and isprime(t*convert(convert(t, base, 10), `+`)+1), [$2..10^4]);

Prog

(PARI) isok(p) = isprime(p) && isprime(p*sumdigits(p)+1); \\ Michel Marcus, Dec 18 2020

Crossrefs

Cf. A007953, A057147.

Subsequence of A119449.

Sequence in context: A296923 A243588 A137977 * A160950 A141168 A259394

Adjacent sequences: A338973 A338974 A338975 * A338977 A338978 A338979

Keyword

nonn,base

Author

J. M. Bergot and Robert Israel, Dec 18 2020

Status

approved