A381372 Smaller of two consecutive primes p and q, both ending with 3, such that q-p = 10n, or -1 if no such primes exist.

283, 3413, 7253, 19333, 45893, 142993, 399283, 542603, 818723, 396733, 3240983, 10863973, 32788543, 8917523, 17652013, 92593183, 80935103, 92510963, 257789053, 481691513, 20831323, 47326693, 607010093, 1461724573, 387096133, 1496441363, 2298026803, 1855047163

Offset

1,1

Links

Table of n, a(n) for n=1..28.

Example

a(1) = 283, because 283 and 283 + 10 = 293 are two consecutive primes with the same last digit 3 and no smaller p has this property.

Prog

(PARI) a(n) = my(p=3); while (!isprime(p) || ((nextprime(p+1)-p) != 10*n), p+=10); p; \\ Michel Marcus, Feb 24 2025

Crossrefs

Cf. A140791, A380785.

Sequence in context: A332676 A142837 A064964 * A372402 A263670 A108826

Adjacent sequences: A381369 A381370 A381371 * A381373 A381374 A381375

Keyword

nonn,base

Author

Jean-Marc Rebert, Feb 23 2025

Status

approved