OFFSET
1,1
COMMENTS
EXAMPLE
The terms (center), their binary indices (left), and their weakly decreasing prime indices (right) begin:
{1,2} 3 (2)
{3} 4 (1,1)
{1,3} 5 (3)
{1,4} 9 (2,2)
{3,4} 12 (2,1,1)
{1,3,4} 13 (6)
{2,3,4} 14 (4,1)
{5} 16 (1,1,1,1)
{1,5} 17 (7)
{3,5} 20 (3,1,1)
{2,3,5} 22 (5,1)
{1,2,3,5} 23 (9)
{1,4,5} 25 (3,3)
{2,3,4,5} 30 (3,2,1)
{1,2,3,4,5} 31 (11)
{1,2,6} 35 (4,3)
{3,6} 36 (2,2,1,1)
{1,3,6} 37 (12)
{2,3,6} 38 (8,1)
{1,2,3,6} 39 (6,2)
{2,4,6} 42 (4,2,1)
{1,2,4,6} 43 (14)
MATHEMATICA
Select[Range[2, 100], EvenQ[IntegerLength[#, 2]+PrimePi[FactorInteger[#][[-1, 1]]]]&]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, May 14 2024
STATUS
approved