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 A242786 #30 Dec 10 2022 01:27:39 %S A242786 2,3,3,43,7,41,23,643,17,557,251,13183,1999,10007,107 %N A242786 Least prime p such that p^n and p^n+1 have the same number of prime factors (counted with multiplicity) or 0 if no such number exists. %C A242786 Also least number k > 1 such that k^n and k^n+1 have the same number of prime factors. %C A242786 Since the data values are prime, p^n and p^n+1 have n prime factors. %C A242786 a(21) = 1151. %C A242786 a(17) = 5119. - _Michel Marcus_, Sep 21 2018 %C A242786 a(16) > 10^6; a(18) = 33577; a(19) = 48383. - _Jon E. Schoenfield_, Sep 22 2018 %C A242786 a(20) > 10^6. - _Jon E. Schoenfield_, Sep 28 2018 %C A242786 a(16) <= 206874667. - _Daniel Suteu_, Dec 09 2022 %e A242786 2^3 = 8 and 2^3 + 1 = 9 do not have the same number of prime factors. 3^3 = 27 and 3^3 + 1 = 28 both have 3 prime factors (27 = 3*3*3 and 28 = 7*2*2). Thus, a(3) = 3. %o A242786 (PARI) a(n)=forprime(p=1,oo,if(bigomega(p^n+1)==n,return(p))); \\ _Michel Marcus_, Sep 21 2018 %Y A242786 Cf. A001222 (bigomega), A241793. %K A242786 nonn,more,hard %O A242786 1,1 %A A242786 _Derek Orr_, May 22 2014 %E A242786 Data restricted to known terms by _Michel Marcus_, Sep 21 2018 %E A242786 a(12) & a(14) from _Michel Marcus_, Sep 21 2018