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 A101753 #33 Jul 09 2023 09:40:12
%S A101753 1,2,6,126,8598
%N A101753 Numbers m such that Sum_{k=0..m} m^k is prime.
%C A101753 Value of sum for m = 126 has been checked to be probably prime with the isprime functions of PARI and Maple V. Also checked with ECM - see link.
%C A101753 Note that m+1 must be prime and hence a(n) = A088856(n) - 1. Another way to compute the number is (m^(m + 1) - 1)/(m - 1). - _T. D. Noe_, Dec 15 2004
%C A101753 Value of sum for m = 126 has been certified prime with Primo. - _Ryan Propper_, Jul 11 2005
%H A101753 Dario Alpern, <a href="https://www.alpertron.com.ar/ECM.HTM">Integer factorization calculator</a>.
%F A101753 a(n) = A088856(n) - 1.
%e A101753 The number 6 is in this sequence because 6^0 + 6^1 + 6^2 + 6^3 + 6^4 + 6^5 + 6^6 = (6^7 - 1)/5 = 55987 is prime.
%Y A101753 Cf. A031973.
%Y A101753 Cf. A088856 (primes p such that cyclotomic(p,p-1) is prime).
%K A101753 nonn,more
%O A101753 1,2
%A A101753 Mark Hudson (mrmarkhudson(AT)hotmail.com), Dec 15 2004
%E A101753 One more term from _T. D. Noe_, Dec 15 2004
%E A101753 Edited by _Thomas Ordowski_, Sep 02 2021