login
A106555
Concatenation of the two divisors of a semiprime, largest divisor first.
0
22, 32, 33, 52, 72, 53, 73, 112, 55, 132, 113, 172, 75, 192, 133, 232, 77, 173, 115, 193, 292, 312, 135, 233, 372, 117, 412, 175, 432, 293, 137, 313, 472, 195, 532, 373, 235, 592, 177, 1111, 612, 413, 433, 197, 672, 473, 712, 1311, 295, 732
OFFSET
1,1
EXAMPLE
First semiprime is 4; 4 is 2*2 -> 22.
Second semiprime is 6; 6 is 3*2 -> 32.
Third semiprime is 9; 9 is 3*3 -> 33.
Fourth semiprime is 10; 10 is 5*2 -> 52.
PROG
(PARI) glue(a, b)=10^#Str(b)*a+b;
for(n=4, 1e3, if(bigomega(n)==2, f=factor(n)[, 1]; print1(glue(f[#f], f[1])", "))) \\ Charles R Greathouse IV, Oct 04 2011
CROSSREFS
Sequence in context: A239431 A335348 A179282 * A106557 A142347 A217059
KEYWORD
base,easy,nonn
AUTHOR
Eric Angelini, May 09 2005
STATUS
approved