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 A381372 #33 Mar 08 2025 17:30:56 %S A381372 283,3413,7253,19333,45893,142993,399283,542603,818723,396733,3240983, %T A381372 10863973,32788543,8917523,17652013,92593183,80935103,92510963, %U A381372 257789053,481691513,20831323,47326693,607010093,1461724573,387096133,1496441363,2298026803,1855047163 %N 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. %e A381372 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. %o A381372 (PARI) a(n) = my(p=3); while (!isprime(p) || ((nextprime(p+1)-p) != 10*n), p+=10); p; \\ _Michel Marcus_, Feb 24 2025 %Y A381372 Cf. A140791, A380785. %K A381372 nonn,base %O A381372 1,1 %A A381372 _Jean-Marc Rebert_, Feb 23 2025