cp's OEIS Frontend

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.

A174129 Numerators of the first column of the table of fractions generated by the Akiyama-Tanigawa transform from a first row A164555(k)/A027642(k).

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%I A174129 #28 Feb 18 2022 23:09:01
%S A174129 1,1,-1,-1,31,7,-1051,-201,56911,18311,-24346415,-4227881,
%T A174129 425739604981,2082738855,-759610463437,-1935668684041,
%U A174129 91825384886337407,3104887811293639,-333936446105326262497,-8039608511660213481,496858217433153341005061
%N A174129 Numerators of the first column of the table of fractions generated by the Akiyama-Tanigawa transform from a first row A164555(k)/A027642(k).
%C A174129 The first 6 rows if the table generated by iterative application of the Akiyama-Tanigawa transform starting with a header row of fractions  A164555(k)/A027642(k) are:
%C A174129   1, 1/2, 1/6, 0, -1/30, 0, 1/42, 0, -1/30, 0, 5/66, 0, -691/2730, 0, 7/6, ...
%C A174129   1/2, 2/3, 1/2, 2/15, -1/6, -1/7, 1/6, 4/15, -3/10, -25/33, 5/6, 1382/455, ...
%C A174129   -1/6, 1/3, 11/10, 6/5, -5/42, -13/7, -7/10, 68/15, 453/110, -175/11, ...
%C A174129   -1/2, -23/15, -3/10, 554/105, 365/42, -243/35, -1099/30, 548/165, 19827/110, ...
%C A174129   31/30, -37/15, -1171/70, -478/35, 469/6, 1247/7, -6153/22, -46708/33, ...
%C A174129   7/2, 599/21, -129/14, -38566/105, -20995/42, 211515/77, 524699/66, ...
%C A174129 The numerators of the leftmost column define the current sequence.
%H A174129 D. Merlini, R. Sprugnoli and M. C. Verri, <a href="https://www.emis.de/journals/INTEGERS/papers/f5/f5.Abstract.html">The Akiyama-Tanigawa Transformation</a>, Integers, 5 (1) (2005) #A05.
%F A174129 a(n) = numerator(Sum_{j=0..n} (-1)^(n-j)*j!*Stirling2(n,j)*B(j)), where B are the Bernoulli numbers A164555/A027642. - _Fabián Pereyra_, Jan 06 2022
%p A174129 read("transforms3") ;
%p A174129 A174129 := proc(n) Lin := [bernoulli(0),-bernoulli(1),seq(bernoulli(k),k=2..n+1)] ; for r from 1 to n do Lin := AKIYATANI(Lin) ; end do; numer(op(1,Lin)) ; end proc:
%t A174129 a[0, k_] := a[0, k] = BernoulliB[k]; a[0, 1] = 1/2; a[n_, k_] := a[n, k] = (k+1)*(a[n-1, k] - a[n-1, k+1]); a[n_] := a[n, 0] // Numerator; Table[a[n], {n, 0, 20}] (* _Jean-François Alcover_, Aug 14 2012 *)
%Y A174129 Cf. A141056 (denominators), A174110, A174111 (first row).
%Y A174129 Cf. A164555, A027642, A048993.
%K A174129 frac,sign
%O A174129 0,5
%A A174129 _Paul Curtz_, Mar 09 2010