OFFSET
1,1
COMMENTS
Subsequence of A014311. [R. J. Mathar, Feb 24 2010]
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1) = 21 = 10101_2.
a(2) = 37 = 100101_2.
a(3) = 41 = 101001_2.
MAPLE
seq(seq(seq(2^a+2^b+2^c, c=0..b-2), b=2..a-2), a=4..10); # Robert Israel, Dec 19 2016
MATHEMATICA
e31sQ[n_]:=Module[{idn2=IntegerDigits[n, 2]}, Total[idn2]==3 && SequenceCount[ idn2, {1, 1}]==0]; Select[Range[700], e31sQ] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 20 2018 *)
CROSSREFS
KEYWORD
base,nonn
AUTHOR
David Koslicki (koslicki(AT)math.psu.edu), Feb 22 2010
EXTENSIONS
More terms from R. J. Mathar, Feb 24 2010
STATUS
approved