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 A261408 #13 Jun 29 2019 19:46:22 %S A261408 21,34,192,310,373,536,12000 %N A261408 Numbers k such that A260864(k) is a prime or probable prime, where A260864(k) is the number whose base-14 representation is the concatenation of the base-14 representations of (1, ..., k, k-1, ..., 1). %C A261408 The subsequence of those A261171(n) for which A261172(n) = 14. - _M. F. Hasler_, Aug 23 2015 %D A261408 David Broadhurst, email to N. J. A. Sloane, Aug 23 2015 %Y A261408 Cf. A260343, A260864. %Y A261408 See also A260871 which lists all primes of the form A[b](k), and A261171 and A261172 which list the k and b values of these primes. - _M. F. Hasler_, Aug 23 2015 %K A261408 nonn,more %O A261408 1,1 %A A261408 _N. J. A. Sloane_, Aug 22 2015 %E A261408 More explicit title from _M. F. Hasler_, Aug 23 2015