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.

A119844 Records in A119842.

Original entry on oeis.org

1, 2, 6, 14, 22, 252, 17526, 9278038, 23694308, 1186593143406, 789632365568454684, 3199548374111958458274, 849440501364681630324594977448
Offset: 1

Views

Author

Antti Karttunen, Jun 04 2006

Keywords

Crossrefs

a(n) = A119842(A119843(n)).

Programs

  • Mathematica
    b[s_, t_] := b[s, t] = If[Length[s] < 1, 1, Sum[If[Mod[PrimeOmega[x], 2] == 1 - t && Length[Select[s, Mod[#, x] == 0 &]] == 1, b[s~Complement~{x}, 1 - t], 0], {x, s}]]; a[n_] := a[n] = Module[{l, m}, l = Sort[ FactorInteger[n], #1[[2]] > #2[[2]] &]; m = Product[Prime[i]^l[[i]][[2]], {i, 1, Length[l]}]; b[Divisors[m][[2 ;; -2]], Mod[PrimeOmega[m], 2]]]; Reap[For[record = 0; k = 1, k < 10^4, k++, If[a[k] > record, record = a[k]; Print[k, " ", a[k]]; Sow[a[k]]]]][[2, 1]] (* Jean-François Alcover, Mar 03 2016, after Alois P. Heinz *)

Extensions

a(9)-a(13) from Alois P. Heinz, Feb 26 2016