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 A070523 #32 Nov 18 2022 10:14:03 %S A070523 3,6,7,14,19,31,34,66,93,307,402,421,600,848,1022,1057,1906,3772,4184, %T A070523 4364 %N A070523 Numbers k such that cyclotomic(k, prime(k)) is a prime number. %C A070523 Values corresponding to a(3)=7 through a(13)=600 have been certified prime with Primo. Their sizes in decimal digits are 8, 10, 33, 64, 35, 51, 162, 1012, 455, 1455 and 584, respectively. Values corresponding to a(14) through a(17) are probable primes with lengths 1588, 1689, 3535 and 4014 decimal digits. a(18)>2000. - _Rick L. Shepherd_, Jul 10 2002 %C A070523 All terms <= 1906 have been proven with PARI's ECPP. No other terms <= 20000. - _Lucas A. Brown_, Jan 03 2021 %H A070523 Lucas A. Brown, <a href="https://github.com/lucasaugustus/oeis/blob/main/A070523.py">A070523.py</a>. %e A070523 For n=7: 1+x+x^2+x^3+x^4+x^5+x^6 at x=prime(7)=17 gives a prime 25646167. %o A070523 (PARI) for(n=1,2000, if(isprime(eval(polcyclo(n, prime(n)))), print1(n, ", "))) %Y A070523 Cf. A070518, A070519, A070520, A070521, A070522. %K A070523 nonn,more %O A070523 1,1 %A A070523 _Labos Elemer_, May 02 2002 %E A070523 More terms from _Rick L. Shepherd_, Jul 10 2002 %E A070523 a(18)-a(20) by _Lucas A. Brown_, Jan 02 2021