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 A043298 #20 Jan 09 2024 17:58:07
%S A043298 1,19,31,43,59,67,71,79,97,109,127,139,149,157,163,167,193,197,199,
%T A043298 211,223,227,229,269,307,317,337,349,353,361,379,383,389,401,409,421,
%U A043298 433,439,449,457,463,479,487,499,521,523,541,547,563,569,571,587,589,599
%N A043298 Numbers n such that B(6*n) has denominator 42 where B(2k) are the Bernoulli numbers.
%C A043298 Except for 1 and 361=19^2 terms listed are primes.
%C A043298 Most a(n) are primes p such that 2p+1 is composite A053176. Nonprime a(n) (except a(1) = 1) are the powers or the products of primes from a(n). For example, 361 = 19^2, 589 = 19*31, 961 = 31^2, 1333 = 31*43, 1849 = 43^2, 2071 = 19*109, 2077 = 31*67, 2201 = 31*71, 2449 = 31*79, 2537 = 43*59, 2641 = 19*139, 2881 = 43*67, 2983 = 19*157, 3053 = 43*71, 3173 = 19*167, ..., 6859 = 19^3. - _Alexander Adamchuk_, Jul 28 2006
%H A043298 Enrique Pérez Herrero, <a href="/A043298/b043298.txt">Table of n, a(n) for n=1..50000</a>
%t A043298 Do[s=1+Divisors[n]; s1=Flatten[Position[PrimeQ[s], True]]; s2=Part[s, s1]; If[Equal[s2, {2, 3, 7}], Print[n/6]], {n, 1, 10000}] (* _Alexander Adamchuk_, Jul 28 2006 *)
%t A043298 Select[Range[600],Denominator[BernoulliB[6#]]==42&] (* _Harvey P. Dale_, Jan 09 2024 *)
%Y A043298 Cf. A051225, A053176.
%K A043298 easy,nonn
%O A043298 1,2
%A A043298 _Benoit Cloitre_, Mar 24 2002
%E A043298 Corrected and extended by _Ralf Stephan_, Oct 21 2002
%E A043298 More terms from _Alexander Adamchuk_, Jul 28 2006