A070016 Least m such that Chowla's function value of m [A048050(m)] equals n or 0 if no such number exists.

0, 4, 9, 0, 6, 8, 10, 15, 14, 21, 121, 27, 22, 16, 12, 39, 289, 65, 34, 18, 20, 57, 529, 95, 46, 69, 28, 115, 841, 32, 58, 45, 62, 93, 24, 155, 1369, 217, 44, 63, 30, 50, 82, 123, 52, 129, 2209, 75, 40, 141, 0, 235, 42, 36, 106, 99, 68, 265, 3481, 371, 118, 64, 56, 117

Offset

1,2

Comments

Remark that A070016(n)=A070015(n+1) in accordance with A048995(k)+1=A005114(k).

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Formula

a(n)=Min{x; A048050(x)=n} or a(n)=0 if n is from A048995.

Example

n=127: a(n)=16129, divisors={1,127,16129}, 127=sigma[n]-n-1=127 and 16129 is the smallest.

Mathematica

f1[x_] := DivisorSigma[1, x]-x-1; t=Table[0, {128}]; Do[b=f1[n]; If[b<129&&t[[b]]==0, t[[b]]=n], {n, 1, 1000000}]; t

Crossrefs

Cf. A000203, A001065, A048050, A051444, A007369, A070016, A005114, A048995.

Sequence in context: A021675 A093872 A097906 * A243372 A020802 A085675

Adjacent sequences: A070013 A070014 A070015 * A070017 A070018 A070019

Keyword

nonn

Author

Labos Elemer, Apr 12 2002

Status

approved