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 A050244 #44 Mar 16 2023 08:50:52 %S A050244 3,6,7,8,10,11,12,14,16,22,32,34,38,82,83,106,128,149,218,223,334,412, %T A050244 436,599,647,916,1373,4414,7246,8423,10118,10942,15898,42422,65986 %N A050244 Numbers k such that 2^k + 3^k is a semiprime. %C A050244 Empirically, the smaller factor of 2^a(n) + 3^a(n) is a term of A294132 for all known terms. a(34) > 22000. - _Hugo Pfoertner_, Jul 29 2019 %C A050244 Terms for n >= 34 are probable semiprimes. - _Tyler Busby_, Feb 18 2023 %C A050244 Empirically, this sequence is a subsequence of A093641. No more terms of A093641 less than 10^5 are in this sequence. - _Tyler Busby_, Feb 20 2023 %H A050244 factordb, <a href="http://factordb.com/index.php?query=%283%5E42422%2B2%5E42422%29%2F13">Status of (3^42422+2^42422)/13</a>. %e A050244 a(1)=3 because 2^3 + 3^3 = 5 * 7. %e A050244 a(2)=6 because 2^6 + 3^6 = 13 * 61. %e A050244 a(3)=7 because 2^7 + 3^7 = 5 * 463. %e A050244 a(4)=8 because 2^8 + 3^8 = 17 * 401. %e A050244 a(5)=10 because 2^10 + 3^10 = 13 * 4621. %e A050244 a(6)=11 because 2^11 + 3^11 = 5 * 35839. %e A050244 a(7)=12 because 2^12 + 3^12 = 97 * 5521. %e A050244 a(8)=14 because 2^14 + 3^14 = 13 * 369181. %e A050244 a(9)=16 because 2^16 + 3^16 = 3041 * 14177. %e A050244 a(10)=22 because 2^22 + 3^22 = 13 * 2414250301. %e A050244 a(11)=32 because 2^32 + 3^32 = 1153 * 1607133116929. %e A050244 a(12)=34 because 2^34 + 3^34 = 13 * 1282861452271981. %e A050244 a(13)=38 because 2^38 + 3^38 = 13 * 103911691734684541. %e A050244 a(14)=82 because 2^82 + 3^82 = 13 * 102329189594547549657540565413396038701. %e A050244 a(15)=83 because 2^83 + 3^83 = 5 * 798167678837469920188160718521149336927. %e A050244 a(16)=106 because 2^106 + 3^106 = 13 * 28900785585664327723593061693364968422740414514061. %e A050244 a(17)=128 because 2^128 + 3^128 = 257 * 45876204582640401445607833244277975113391731388650867226881. %e A050244 a(18)=149 because 2^149 + 3^149 = 5 * 24665899002341798194980052306171212216360861465143461865961807325057879. %Y A050244 Cf. A001358, A007689, A082101, A294132. %K A050244 nonn,more,hard %O A050244 1,1 %A A050244 _Hugo Pfoertner_, May 08 2003 %E A050244 Corrected and extended by _Hugo Pfoertner_, May 12 2003 %E A050244 More terms from Herman Jamke (hermanjamke(AT)fastmail.fm), Dec 30 2007 %E A050244 a(28)-a(32) from _Sean A. Irvine_, Nov 05 2009 %E A050244 a(33) from _Hugo Pfoertner_, Jul 29 2019 %E A050244 a(34)-a(35) from _Tyler Busby_, Jan 14 2023