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 A051130 #47 Feb 16 2025 08:32:41 %S A051130 2,3,7,13,42,55,2841 %N A051130 Indices of prime Bell numbers A000110. %C A051130 Bell(2841) has been certified to be a prime using Primo. This took 17 months on a P3-800, a P4-2400 and finally a P4-2800. There are no other terms below 6000. - _Ignacio Larrosa Cañestro_, Feb 13 2004 %C A051130 The next term, if it exists, is > 50000. - _Vaclav Kotesovec_, May 18 2021 %C A051130 No other terms < 100000. - _Mathieu Gouttenoire_, Oct 31 2021 %H A051130 E. T. Bell, <a href="http://www.jstor.org/stable/2300300">Exponential numbers</a>, Amer. Math. Monthly, 41 (1934), 411-419. %H A051130 The Prime Database, <a href="https://primes.utm.edu/primes/page.php?id=68825">93074010508593618333...(6499 other digits)...83885253703080601131</a> %H A051130 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/BellNumber.html">Bell Number</a> %H A051130 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/IntegerSequencePrimes.html">Integer Sequence Primes</a> %e A051130 The Bell numbers Bell(2)=2, Bell(3)=5, Bell(7)=877 etc. are primes. %t A051130 Reap[For[n = 1, n <= 3000, n++, If[PrimeQ[BellB[n]], Print[n]; Sow[n]]]][[2, 1]] (* _Jean-François Alcover_, Jun 05 2012 *) %t A051130 Select[Range[2900],PrimeQ[BellB[#]]&] (* _Harvey P. Dale_, Nov 08 2012 *) %o A051130 (Magma) [n: n in [0..1000]|IsPrime(Bell(n))]; // _Vincenzo Librandi_, Jan 30 2016 %Y A051130 Cf. A000110, A051131. %K A051130 hard,nonn,nice %O A051130 1,1 %A A051130 _Ignacio Larrosa Cañestro_