A081716 Smallest number x such that phi(x)=A000010(x) has exactly n different decimal digits.

2, 11, 103, 1033, 10247, 102359, 1023487, 10234759, 102345979, 1023475969

Offset: 1

Author

Labos Elemer, Apr 04 2003

Keywords

• nonn
• fini
• full
• base

Examples

			phi applied to the sequence gives: 1, 10, 102, 1032, 10246, 102358, 1023486, 10234758, 102345978, ...
		

Crossrefs

Cf. A007809, A038378, A000010.

Programs

Mathematica

f[x_] := Length[Union[IntegerDigits[x]]]
t=Table[0, {10}];
Do[s=f[n]; If[PrimeQ[n]&&s<11&&t[[s]]==0,
t[[s]]=n], {n, 1, 10000000000}];

Extensions

a(10) from Donovan Johnson, Feb 05 2010