OFFSET
1,2
EXAMPLE
a(1)=1 because composite(1) * 2^(1-3) = 4 * 2^(-2) = 1;
a(2)=3 because composite(2) * 2^(2-3) = 6 * 2^(-1) = 3;
a(3)=8 because composite(3) * 2^(3-3) = 8 * 2^0 = 8.
MATHEMATICA
#[[1]]*2^(#[[2]]-3)&/@Module[{cs=Select[Range[50], CompositeQ]}, Thread[ {cs, Range[Length[cs]]}]] (* Harvey P. Dale, Oct 08 2018 *)
CROSSREFS
KEYWORD
nonn,less
AUTHOR
Gerasimov Sergey, Apr 02 2014
STATUS
approved