%I M4191 N1747 #48 Mar 08 2023 03:41:07
%S 1,6,30,84,90,132,5460,360,1530,7980,13860,8280,81900,1512,3480,
%T 114576,117810,1260,3838380,32760,568260,1191960,869400,236880,
%U 9746100,525096,629640,351120,198360,42480,1362881520,4324320,1093950,33008220,434700,843480,46233287100,102702600,1081080
%N Denominator in Feinler's formula for unsigned Bernoulli number |B_{2n}|.
%C A002443/A002444 = |B_{2n}| (see also A000367/A002445).
%D H. T. Davis, Tables of the Mathematical Functions. Vols. 1 and 2, 2nd ed., 1963, Vol. 3 (with V. J. Fisher), 1962; Principia Press of Trinity Univ., San Antonio, TX, Vol. 2, p. 208.
%D N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
%D N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H H. T. Davis, <a href="/A002443/a002443.pdf">Tables of the Mathematical Functions</a>, Vols. 1 and 2, 2nd ed., 1963, Vol. 3 (with V. J. Fisher), 1962; Principia Press of Trinity Univ., San Antonio, TX. [Annotated scan of pages 204-208 of Volume 2.]
%H Milan Janjic, <a href="http://www.pmfbl.org/janjic/">Enumerative Formulas for Some Functions on Finite Sets</a>
%H <a href="/index/Be#Bernoulli">Index entries for sequences related to Bernoulli numbers.</a>
%F Let p_i denote the i-th prime, and let V(n,i) = floor(n/(prime(i)-1)) = A266742(n,i).
%F Then a(n) = (Prod_i (p_i)^V(n,i))/n!.
%F (See Davis, Vol. 2, p. 206, first displayed equation, where a(n) appears as d_{2k}.)
%p with(numtheory);
%p g:=proc(m) local i,n; n:=2*m;
%p mul(ithprime(i)^floor(n/(ithprime(i)-1)),i=1..pi(n+1));
%p %/n!;
%p end;
%p [seq(g(m),m=0..40)]; # _N. J. A. Sloane_, Jan 08 2016
%t a[n_] := Product[Prime[i]^Floor[2n/(Prime[i]-1)], {i, 1, PrimePi[2n+1]}]/(2n)!;
%t Table[a[n], {n, 0, 40}] (* _Jean-François Alcover_, Mar 08 2023 *)
%Y Cf. A002443, A000367, A002445, A266742, A266743, A266911.
%K nonn,frac
%O 0,2
%A _N. J. A. Sloane_
%E Name amended upon suggestion by _T. D. Noe_, by _M. F. Hasler_, Jan 05 2016
%E Edited with new definition, more terms, and scan of source by _N. J. A. Sloane_, Jan 08 2016