OFFSET
1,2
EXAMPLE
The 5th lower twin prime is 29. 2+9=11 a prime, so 5 is listed.
The 4th lower twin prime is 17. 1+7=8 so 4 is missing from the table.
PROG
(PARI) sdtwprime(n) = { local(x, y); for(x=1, n, y=sumdigits(twinl(x)); if(isprime(y), print1(x", ") ) ) } sumdigits(n) = \ The sum of the digits of n { local(x, j, s=0); x=digits(n); for(j=1, length(x), s+=x[j]; ); return(s) } digits(n) = \ The vector of the digits of n { return(eval(Vec(Str(n)))) }
CROSSREFS
KEYWORD
easy,nonn,base
AUTHOR
Cino Hilliard, Mar 13 2005
STATUS
approved