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 A144035 #19 Aug 27 2018 22:43:46 %S A144035 0,1,1,4,13,51,197,828,3526,15538,69627,317564,1466868,6853320, %T A144035 32317354,153636769,735493374,3542610091,17155811156,83480667707, %U A144035 407969449010,2001479974330,9853652529076,48666276924852,241059431701113,1197237945360797,5960804381552300 %N A144035 Shifts left when Euler transform applied 3 times. %H A144035 Alois P. Heinz, <a href="/A144035/b144035.txt">Table of n, a(n) for n = 0..1000</a> %H A144035 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a> %p A144035 b:= ((proc(p) local b; b:= proc(n) option remember; `if`(n=0, 1, %p A144035 add(add(d*p(d), d=numtheory[divisors](j))*b(n-j), j=1..n)/n) %p A144035 end end)@@3)(a): %p A144035 a:= n-> b(n-1): %p A144035 seq(a(n), n=0..25); # revised _Alois P. Heinz_, Aug 27 2018 %t A144035 etr[p_] := Module[{b}, b[n_] := b[n] = If[n == 0, 1, Sum[Sum[d*p[d], {d, Divisors[ j]}]*b[n-j], {j, 1, n}]/n]; b]; A[n_, k_] := Module[{a, b, t}, b[1] = etr[a]; For[ t = 2, t <= k, t++, b[t] = etr[b[t-1]]]; a = Function[m, If[m == 1, 1, b[k][m-1]]]; a[n]]; Table[ A[n, 3], {n, 0, 30} ] (* _Jean-François Alcover_, Mar 05 2015, after _Alois P. Heinz_ *) %Y A144035 3rd column of A144042. %Y A144035 Cf. A316103. %K A144035 eigen,nonn %O A144035 0,4 %A A144035 _Alois P. Heinz_, Sep 07 2008