STATUS
proposed
approved
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Revision History for A144316
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STATUS
editing
proposed
MATHEMATICA
dc[b_, c_] := Module[{proc}, proc[n_] := proc[n] = Sum[b[d]*c[n/d], {d, If[n < 0, {}, Divisors[n]]}]; proc];
A[n_, k_] := Module[{a, b, t}, b[1] = dc[a, a]; For[t = 2, t <= k, t++, b[t] = dc[b[t-1], b[t-1]]]; a = Function[m, If[m == 1, 1, b[k][m-1]]]; a[n]];
a[n_] := A[n, 2];
Array[a, 30] (* Jean-François Alcover, Jun 11 2018, after Alois P. Heinz *)
STATUS
approved
editing
STATUS
editing
approved
MAPLE
k:=2: with (numtheory): dc:= proc(b, c) proc(n) option remember; add (b(d) *c(n/d), d=`if`(n<0, {}, divisors(n))) end end: a:='a': b[1]:= dc(a, a): for t from 2 to k do b[t]:= dc(b[t-1], b[t-1]) od: a:= n-> `if`(n=1, 1, b[k](n-1)): seq (a(n), n=1..30);
STATUS
approved
editing
STATUS
editing
approved
FORMULA
a(n) ~ c * 4^n, where c = 0.0724091505138381672774074945426621544789572745186499358668403190389... . - Vaclav Kotesovec, Sep 03 2014
STATUS
approved
editing
STATUS
editing
approved
LINKS
N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
LINKS
Alois P. Heinz, <a href="/A144316/b144316.txt">Table of n, a(n) for n = 1..500</a>