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A262094
Orders m for which the only perfect digital invariants of order m are 0 and 1.
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
1,2
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.
EXAMPLE
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
KEYWORD
nonn,base,more
AUTHOR
Don Knuth, Sep 10 2015
STATUS
approved