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A091066
Numbers having in binary representation at least one proper prefix that is also a suffix.
5
3, 5, 7, 9, 10, 11, 13, 15, 17, 18, 19, 21, 22, 23, 25, 27, 29, 31, 33, 34, 35, 36, 37, 38, 39, 41, 42, 43, 45, 46, 47, 49, 51, 53, 54, 55, 57, 59, 61, 63, 65, 66, 67, 68, 69, 70, 71, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 85, 86, 87, 89, 90, 91, 93, 94, 95, 97, 99, 101
OFFSET
1,1
COMMENTS
A091064(a(n)) > 0, complement of A091065.
Includes all odd numbers > 1. - Robert Israel, Feb 05 2016
MAPLE
f:= proc(n) local L, m;
if n::odd then return true fi;
L:= convert(n, base, 2);
for m from 2 to nops(L)-1 do
if L[1..m] = L[-m..-1] then return true fi;
od:
false
end proc:
select(f, [$2..101]); # Robert Israel, Feb 05 2016
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Reinhard Zumkeller, Dec 17 2003
STATUS
approved