OFFSET
1,1
COMMENTS
EXAMPLE
The terms (center), their binary indices (left), and their prime indices (right) begin:
{3} 4 (1,1)
{1,3} 5 (3)
{1,2,4} 11 (5)
{3,4} 12 (2,1,1)
{5} 16 (1,1,1,1)
{1,5} 17 (7)
{3,5} 20 (3,1,1)
{1,2,3,5} 23 (9)
{1,4,5} 25 (3,3)
{3,4,5} 28 (4,1,1)
{1,2,3,4,5} 31 (11)
{1,2,6} 35 (4,3)
{3,6} 36 (2,2,1,1)
{1,4,6} 41 (13)
{3,4,6} 44 (5,1,1)
{1,2,3,4,6} 47 (15)
{5,6} 48 (2,1,1,1,1)
{3,5,6} 52 (6,1,1)
{1,2,3,5,6} 55 (5,3)
{1,2,4,5,6} 59 (17)
{3,4,5,6} 60 (3,2,1,1)
{7} 64 (1,1,1,1,1,1)
MATHEMATICA
bix[n_]:=Join@@Position[Reverse[IntegerDigits[n, 2]], 1];
prix[n_]:=If[n==1, {}, Flatten[Cases[FactorInteger[n], {p_, k_}:>Table[PrimePi[p], {k}]]]];
Select[Range[100], EvenQ[Min[bix[#]]+Min[prix[#]]]&]
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Gus Wiseman, May 06 2024
STATUS
approved