A262094 Orders m for which the only perfect digital invariants of order m are 0 and 1.

1, 2, 12, 15, 18, 22, 26, 28, 30, 40, 41, 48, 50, 52, 58, 80, 82, 88, 98, 103, 106, 130, 135, 136, 138, 139, 140, 142, 150, 152, 159, 164, 165, 166

Offset: 1

Author

Don Knuth, Sep 10 2015

Keywords

• nonn
• base
• more

Comments

a(1), a(2), ... are the indices m for which A255668(m)=2, also A003321(m)=0, also A046761(m)=1.

The values seem to appear in clusters.

Examples

			a(3)=12 because there's no solution to x=(x_{12}...x_1x_0)_{10} = x_{12}^{12}+...+x_1^{12}+x_0^{12} except x=0 and x=1.
		

Crossrefs

Cf. A003321, A046761, A255668.