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 A050236 #31 Feb 16 2025 08:32:40 %S A050236 1,9,12,1262 %N A050236 Indices of consecutive squares palindromic primes; x such that x^2 + (x+1)^2 is palindromic and prime. %C A050236 No other terms < 20000000000. - _Patrick De Geest_, Aug 15 1999 %H A050236 Patrick De Geest, <a href="http://www.worldofnumbers.com/sumsquare.htm">Palindromic Sums of Squares of Consecutive Integers</a> %H A050236 Carlos Rivera, <a href="http://www.primepuzzles.net/puzzles/puzz_014.htm">Puzzle 14. Pal-Primes and sum of powers</a>, The Prime Puzzles & Problems Connection. %H A050236 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PalindromicPrime.html">Palindromic Prime</a> %t A050236 Flatten[Position[Total/@Partition[Range[1300]^2,2,1],_?(PrimeQ[#] && IntegerDigits[#]==Reverse[IntegerDigits[#]]&)]] (* _Harvey P. Dale_, Dec 09 2014 *) %o A050236 (PARI) isok(m) = my(p=m^2+(m+1)^2); if (isprime(p), my(d=digits(p)); (d == Vecrev(d))); \\ _Michel Marcus_, Jan 05 2019 %Y A050236 Cf. A050239. %Y A050236 Intersection of A027861 and A027571. %K A050236 nonn,nice,hard,base %O A050236 1,2 %A A050236 _Eric W. Weisstein_