OFFSET
1,1
FORMULA
EXAMPLE
First semiprime is 4; 4 is 2*2; 26=4+22.
Second semiprime is 6; 6 is 2*3; 29=6+23.
Third semiprime is 9; 9 is 3*3; 41=9+33.
Fourth semiprime is 10; 10 is 2*5; 35=10+25.
MATHEMATICA
R=165; SP=Select[Range[R], PrimeOmega[#]==2&]; FromDigits@ Flatten[IntegerDigits@ Table[#1, {#2}] & @@@ FactorInteger@ #] & /@ SP +SP (* James C. McMahon, Feb 18 2024 *)
CROSSREFS
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, May 09 2005
EXTENSIONS
More terms from Reinhard Zumkeller, May 19 2005
Typo corrected by James C. McMahon, Feb 06 2024
STATUS
approved