OFFSET
1,1
COMMENTS
The number of members of A001359 from 100*n-99 to 100*n-3. - Robert Israel, Jul 19 2017
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
FORMULA
MAPLE
f:= proc(n) local P;
P:= select(isprime, {seq(i, i=100*n-99..100*n-1, 2)});
nops(P intersect map(`+`, P, 2))
end proc:
map(f, [$1..200]); # Robert Israel, Jul 19 2017
MATHEMATICA
Table[Count[Prime@ Range[Boole[n == 1] + PrimePi[100 (n - 1) + 1], PrimePi[100 n] - 1], _?(PrimeQ[# + 2] &)], {n, 105}] (* Michael De Vlieger, Jul 20 2017 *)
PROG
(PARI) a(n)=my(s=0); forprime(p=100*n-99, 100*n-2, if(isprime(p+2), s++)); s \\ Charles R Greathouse IV, Feb 03 2011
(Python)
from sympy import primerange, isprime
def a(n):
s=0
for p in primerange(100*n - 99, 100*n - 1):
if isprime(p + 2):s+=1
return s
print([a(n) for n in range(1, 201)]) # Indranil Ghosh, Jul 20 2017, after PARI code
CROSSREFS
KEYWORD
nonn
AUTHOR
Ki Punches, Mar 15 2009
EXTENSIONS
Corrected by Ray Chandler, May 23 2009
STATUS
approved