login
This site is supported by donations to The OEIS Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A119844 Records in A119842. 2
1, 2, 6, 14, 22, 252, 17526, 9278038, 23694308, 1186593143406, 789632365568454684, 3199548374111958458274, 849440501364681630324594977448 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..13.

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-Fran├žois Alcover, Mar 03 2016, after Alois P. Heinz *)

CROSSREFS

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

Sequence in context: A074729 A099901 A119846 * A016060 A307643 A239877

Adjacent sequences:  A119841 A119842 A119843 * A119845 A119846 A119847

KEYWORD

nonn

AUTHOR

Antti Karttunen, Jun 04 2006

EXTENSIONS

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

STATUS

approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified October 14 14:26 EDT 2019. Contains 328018 sequences. (Running on oeis4.)