|
|
A129697
|
|
Sum of isolated primes < 10^n.
|
|
0
|
|
|
2, 577, 51896, 4009989, 345281974, 30126035380, 2657646397769, 238004015750349, 21505022353019864, 1960179022139638131, 180020101551309284879, 16639947666244921992434
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Also A046731(n) - A118552(n) + 5. This agrees with the program in the link up to n = 12.
|
|
LINKS
|
Cino Hilliard, Sum of Isolated primes, message 38 in seqfun Yahoo group, providing code for gcc (needs formatting to become compilable), Jun 5, 2007. [Cached copy]
|
|
FORMULA
|
Isolated primes are primes that are not twin prime components.
|
|
EXAMPLE
|
The sum of the isolated primes < 100 = 2+23+37+47+53+67+79+83+89+97 = 577, the second entry in the table.
|
|
PROG
|
(PARI) isoprimes(n) = { local(j, s, x); for(j=1, n, s=0; forprime(x=2, 10^j, if(!isprime(x-2)&&!isprime(x+2), s+=x) ); print1(s", ") ) }
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn,more,hard
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|