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A156913
Numbers n with property that A100486(n) is square.
0
2, 4, 6, 11, 14, 21, 37, 75, 81, 176, 194, 310, 324, 332, 345, 399, 447, 612, 1122, 1209, 1614, 1874, 1921, 2186, 2329, 2482, 2509, 2874, 2940, 2975, 3230, 3611, 4185, 4650, 4923, 5172, 5248, 5543, 5587, 5673, 5714, 5764, 6038, 6078, 6250, 6430, 6976, 7023
OFFSET
1,1
COMMENTS
For n<2*10^6 there are 411 such numbers.
FORMULA
pi(n) + n-th prime = square.
EXAMPLE
n=2 pi(2)+p(2)=2+2=4, n=4 pi(4)+p(4)=2+7=9, n=6 pi(6)+p(6)=3+13=16, etc.
PROG
(PARI) isok(n) = issquare(primepi(n) + prime(n)); \\ Michel Marcus, Oct 15 2013
CROSSREFS
Cf. A100486.
Sequence in context: A068059 A108868 A274261 * A238483 A238487 A138461
KEYWORD
nonn
AUTHOR
Zak Seidov, Feb 18 2009
STATUS
approved