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 A051225 #35 Jun 07 2020 10:28:11
%S A051225 2,4,34,38,62,76,94,118,122,124,142,188,202,206,214,218,236,244,274,
%T A051225 298,302,314,334,362,394,412,422,436,446,454,458,482,514,526,538,542,
%U A051225 566,578,604,622,626,628,634,662,668,674,694,698,706,722,724,734,758
%N A051225 Numbers m such that the Bernoulli number B_{2*m} has denominator 30.
%C A051225 From the von Staudt-Clausen theorem, denominator(B_{2*m}) = product of primes p such that (p-1)|2*m.
%D A051225 B. C. Berndt, Ramanujan's Notebooks Part IV, Springer-Verlag, see p. 75.
%D A051225 G. H. Hardy and E. M. Wright, An Introduction to the Theory of Numbers, 5th ed., Oxford Univ. Press, 1979, Th. 118.
%D A051225 H. Rademacher, Topics in Analytic Number Theory, Springer, 1973, Chap. 1.
%H A051225 T. D. Noe, <a href="/A051225/b051225.txt">Table of n, a(n) for n = 1..1000</a>
%H A051225 Wikipedia, <a href="https://en.wikipedia.org/wiki/Von_Staudt%E2%80%93Clausen_theorem">Von Staudt-Clausen theorem</a>.
%H A051225 <a href="/index/Be#Bernoulli">Index entries for sequences related to Bernoulli numbers</a>.
%F A051225 a(n) = A051226(n)/2. - _Petros Hadjicostas_, Jun 06 2020
%e A051225 The numbers m = 2, 4, 34 are in the list because B_4 = B_8 = -1/30 and B_68 = -78773130858718728141909149208474606244347001/30. - _Petros Hadjicostas_, Jun 06 2020
%t A051225 Cases[Range[760], n_ /; Denominator[BernoulliB[2*n]] == 30] (* _Jean-François Alcover_, Mar 23 2011 *)
%o A051225 (Perl) @p=(2,3,5); $p=5; for($n=4; $n<=1516; $n+=4){while($p<$n+1){$p+=2; next if grep$p%$_==0,@p; push@p,$p; push@c,$p-1; }print$n/2,","if!grep$n%$_==0,@c; }print"\n"
%o A051225 (PARI) is(n)=fordiv(n,d, if(isprime(2*d+1) && d>2, return(0))); n%2==0 \\ _Charles R Greathouse IV_, Jun 21 2017
%Y A051225 Cf. A045979, A051222, A051226, A051227, A051228, A051229, A051230.
%K A051225 nonn,nice,easy
%O A051225 1,1
%A A051225 _N. J. A. Sloane_
%E A051225 More terms and Perl program from _Hugo van der Sanden_
%E A051225 Name edited by _Petros Hadjicostas_, Jun 06 2020