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 A276203 #38 Apr 16 2022 16:46:08 %S A276203 2,76,122,422,2300,5090,7166,58046,91382,234178,314738 %N A276203 Numbers k such that k^9 + 9^k is prime. %C A276203 Numbers k such that A185277(k) is prime. %H A276203 Hans Havermann, <a href="http://chesswanks.com/num/a094133.txt">Indices of A094133 in A076980</a>. %H A276203 Andrey V. Kulsha, <a href="http://www.primefan.ru/xyyxf/primes.html">Factorizations of x^y + y^x for 1 < y < x < 151</a>. %H A276203 P. Leyland, <a href="http://www.leyland.vispa.com/numth/primes/xyyx.htm">Primes and Strong Pseudoprimes of the form x^y + y^x</a>. %e A276203 2 is a term of the sequence, because A185277(2) = 593 is prime. %o A276203 (PARI) is(n) = ispseudoprime(n^9+9^n) %Y A276203 Cf. A064539, A185277, A253471. %K A276203 nonn,hard,more %O A276203 1,1 %A A276203 _Felix Fröhlich_, Aug 27 2016