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 A099051 #11 Feb 16 2025 08:32:54 %S A099051 7,23,159,895,22527,106495,2228223,9961471,192937983,15569256447, %T A099051 66571993087,5085241278463,90159953477631,378231999954943, %U A099051 6614661952700415,477381560501272575,34011184385901985791 %N A099051 p*2^p - 1 where p is prime. %C A099051 This is the subset of Woodall numbers of prime index. The 9th largest known Woodall prime is in this sequence: 12379*2^12379-1, where 12379 is prime, as found by Wilfrid Keller in 1984. Smaller primes are when p = 2, 3, 751. These numbers can also be semiprime, as when p = 159, 163, or 211 and hard to factor as when n = 349 (108 digits). - _Jonathan Vos Post_, Nov 19 2004 %D A099051 Ribenboim, P. The New Book of Prime Number Records. New York: Springer-Verlag, pp. 360-361, 1996 %H A099051 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/WoodallNumber.html">Woodall Numbers</a>. %e A099051 If p=3, 3*2^3 - 1 = 23. %e A099051 If p=11, 11*2^11 - 1 = 22527. %t A099051 Table[ Prime[n]*2^Prime[n] - 1, {n, 17}] (* _Robert G. Wilson v_, Nov 16 2004 *) %Y A099051 Similar to Woodall numbers (A003261). Cf. A002234. %K A099051 nonn,easy %O A099051 1,1 %A A099051 _Parthasarathy Nambi_, Nov 13 2004 %E A099051 More terms from _Robert G. Wilson v_, Nov 15 2004