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 A103479 #18 Dec 22 2018 16:39:04 %S A103479 38,2478782 %N A103479 Positive integers k for which 1 + 6*2^(k+2) divides the Fermat number 1 + 2^2^k. %C A103479 On Keller's linked page, to find the terms, you run through the tables and find all rows with k = 3 and with n exactly 3 greater than m, then that m belongs to this sequence. - _Jeppe Stig Nielsen_, Dec 04 2018 %H A103479 Wilfrid Keller, <a href="http://www.prothsearch.com/fermat.html">Prime factors k*2^n + 1 of Fermat numbers F_m</a> %e A103479 a(1)=38 because 38 is the smallest positive integer k for which 1 + 6*2^(k+2) divides the Fermat number 1 + 2^2^k. %t A103479 aQ[n_] := PowerMod[2, 2^n, 1 + 6*2^(n+2)] == 6*2^(n+2); Select[Range[3000000], aQ] (* _Amiram Eldar_, Dec 04 2018 *) %o A103479 (PARI) isOK(n) = Mod(2, 1+3*2^(n+3))^(2^n) + 1 == 0 \\ _Jeppe Stig Nielsen_, Dec 03 2018 %Y A103479 Cf. A103477, A103478. %K A103479 nonn,bref,hard,more %O A103479 1,1 %A A103479 Serhat Sevki Dincer (mesti_mudam(AT)yahoo.com), Feb 07 2005 %E A103479 Sequence name trimmed by _Jeppe Stig Nielsen_, Dec 03 2018