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

Author

Labos Elemer, Apr 12 2002

Keywords

• nonn

Comments

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

Examples

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

Links

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

Crossrefs

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

Programs

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

Formula

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