OFFSET
1,1
COMMENTS
The k-primes = numbers that are divisible by exactly k primes (counted with multiplicity).
EXAMPLE
"Twin numbers" are (3, 5), (5, 7), (6, 10), (11, 13), (10, 14), (17, 19), (12, 20), (21, 25), (22, 26), (20, 28), (29, 31), (34, 38), (35, 39), (24, 40), (41, 43), (42, 50), (44, 52), (51, 55), (40, 56), (59, 61), (58, 62), (65, 69), (71, 73), ...
MATHEMATICA
Flatten[{#[[3]], #[[1]]}&/@Select[Table[{n, PrimeOmega[n], n-2^PrimeOmega[n], PrimeOmega[ n-2^PrimeOmega[n]]}, {n, 150}], #[[2]]==#[[4]]&]] (* Harvey P. Dale, Mar 23 2024 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
Juri-Stepan Gerasimov, Sep 01 2010
EXTENSIONS
Rewritten by Charles R Greathouse IV, Sep 03 2010
STATUS
approved