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 A137716 #27 Oct 27 2024 16:08:02 %S A137716 1,45,1423,1749,1994,5573,9726,9779,17964,27347,79002,108761,145072, %T A137716 407850,1905090,2010852 %N A137716 Number of digits in the decimal expansion of the n-th Cullen prime. %C A137716 Cullen primes are prime numbers of the form k*2^k+1. This sequence is complete for all values of n up to 3500000. %H A137716 Ray Ballinger and Mark Rodenkirch, <a href="http://web.archive.org/web/20161028015144/http://www.prothsearch.net/cullen.html">Cullen Primes: Definition and Status</a>. %H A137716 James Cullen, <a href="https://archive.org/details/educationaltimes58educ/page/534">Question 15897</a>, The Educational Times, Dec. 1905, p. 534. %H A137716 Allan Cunningham and H. J. Woodall, <a href="https://archive.org/details/messengerofmathe47cambuoft/page/22/mode/2up">Factorisation of Q=(2^q ± q) and (q*2^q ± 1)</a>, The Messenger of Mathematics, Vol. 47 (1917-18), pp. 1-38. %H A137716 Wilfrid Keller, <a href="https://doi.org/10.1090/S0025-5718-1995-1308456-3">New Cullen Primes</a>, Mathematics of Computation, Vol. 64, No. 212 (Ocober 1995), pp. 1733-1741. %F A137716 a(n) = A055642(A050920(n)). [Corrected by _Georg Fischer_, Nov 18 2023] %e A137716 As the sixth Cullen prime, 18496*2^18496 + 1 = 1.311...*10^5572, is a 5573-digit number, we have a(6) = 5573. %Y A137716 Cf. A055642, A005849, A002064. %K A137716 hard,nonn,base,more %O A137716 1,2 %A A137716 _Ant King_, Feb 09 2008 %E A137716 a(15)-a(16) from _Amiram Eldar_, Oct 27 2024