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 A243100 #32 Dec 23 2024 14:53:43 %S A243100 3,7,19,179,543607,129136067,94143168179,11920928949924493, %T A243100 36472996377170722403,61159026180004467059,1341068619659378429383, %U A243100 10301051460877537453973547005699,710542735760100185871124061615149,17763568394002504646778106434649157 %N A243100 Primes of the form x^(y+1)-y^x, for x,y > 0. %C A243100 See A123206 for primes of the form x^y-y^x with x,y>1. If y=1 is allowed, any prime p is obtained for x=p+1; this motivates the "y+1" in the exponent of the present sequence. %C A243100 See also A086877 (and A098463) for primes of the form (x+1)^x-x^x. %C A243100 y=0 would give "Primes of the form x", so y>0 is required. y=1 gives x^2-1 = (x-1)*(x+1) which is only prime for x=2. - _Jens Kruse Andersen_, Aug 23 2014 %H A243100 Jens Kruse Andersen, <a href="/A243100/b243100.txt">Table of n, a(n) for n = 1..59</a> %H A243100 J. S. Gerasimov, <a href="https://web.archive.org/web/*/http://list.seqfan.eu/oldermail/seqfan/2014-August/013480.html">x^(y + 1) - y^x</a>, SeqFan list, Aug 18, 2014 %o A243100 (PARI) a=[];for(S=1,199,for(x=1,S-1,ispseudoprime(p=x^(1+y=S-x)-y^x)&&a=concat(a,p)));vecsort(a) \\ The list calculated this way is probably not complete up to the last terms. E.g., a 46 digit prime is found for x=3, y=97 after three larger terms for smaller S=x+y. %o A243100 (PARI) m=300; a=[]; for(x=1, m+5, for(y=1, m+5, p=x^(y+1)-y^x; if(p<2^m && ispseudoprime(p), a=concat(a, p)))); a=vecsort(a) \\ Compute all terms below 2^m. _Jens Kruse Andersen_, Aug 23 2014 %Y A243100 See also A072164. %K A243100 nonn %O A243100 1,1 %A A243100 _M. F. Hasler_, Aug 19 2014