OFFSET
1,1
COMMENTS
Subsequence of A001422.
David Wells noted that 23 is the largest integer that is not the sum of distinct powers.
REFERENCES
David Wells, The Penguin Dictionary of Curious and Interesting Numbers, Penguin 1987, p. 101.
EXAMPLE
22 is not in the sequence since 22 = 1 + 2^2 + 2^3 + 3^2.
MATHEMATICA
PerfectPowerQ[n_] := n==1 || GCD@@FactorInteger[n][[All, 2]]>1; a=Select[Range[128], PerfectPowerQ[#] &]; nn = Dimensions[a][[1]]; t=Rest[CoefficientList[Series[Product[(1 + x^a[[k]]), {k, nn}], {x, 0, a[[nn]]}], x]]; Flatten[Position[t, 0]]
CROSSREFS
KEYWORD
nonn,fini,full
AUTHOR
Amiram Eldar, Apr 01 2017
STATUS
approved