A240135 a(n) = composite(n)*2^(n - 3).

1, 3, 8, 18, 40, 96, 224, 480, 1024, 2304, 5120, 10752, 22528, 49152, 102400, 212992, 442368, 917504, 1966080, 4194304, 8650752, 17825792, 36700160, 75497472, 159383552, 327155712, 671088640, 1409286144, 2952790016, 6039797760, 12348030976, 25769803776

Offset

1,2

Links

Table of n, a(n) for n=1..32.

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

Cf. A002808.

Sequence in context: A294591 A080692 A117080 * A066425 A026679 A371682

Adjacent sequences: A240132 A240133 A240134 * A240136 A240137 A240138

Keyword

nonn,less

Author

Gerasimov Sergey, Apr 02 2014

Status

approved