OFFSET
1,1
EXAMPLE
4 is ok because sp(4)=10, sp(5)=14, 14-10=sp(1), sp(n)=A001358(n)=n-th semiprime.
PROG
(PARI) lista(nn) = {vec = vector(nn, i, i); sp = select(i->(bigomega(i)==2), vec); for (i = 1, #sp-1, if (bigomega(sp[i+1]-sp[i]) == 2, print1(i, ", ")); ); } \\ Michel Marcus, Oct 06 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
Zak Seidov, Jun 27 2005
STATUS
approved