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A228865 Primes of the form n^2 + pi(n). 1
5, 11, 53, 149, 331, 449, 1307, 1381, 1777, 2039, 2719, 3041, 3617, 3739, 4243, 4643, 4919, 6263, 7079, 9049, 9629, 12799, 16931, 18257, 20483, 21059, 24061, 32441, 32803, 34267, 38069, 42071, 46703, 49331, 53411, 57173, 64063, 68699, 74587, 75683, 105691, 110291 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Conjecture: the sequence is infinite.

LINKS

K. D. Bajpai, Table of n, a(n) for n = 1..2000

EXAMPLE

a(6)= 449 which is a prime. 21^2+pi(21) = 441 + 8 = 449.

MAPLE

with(numtheory): KD:= proc() local a, b;  a:= n^2+pi(n); if isprime(a) then RETURN(a): fi; end: seq(KD(), n=1..1000);

CROSSREFS

Cf. A076757

Sequence in context: A197958 A094107 A107009 * A149527 A201180 A109546

Adjacent sequences:  A228862 A228863 A228864 * A228866 A228867 A228868

KEYWORD

nonn

AUTHOR

K. D. Bajpai, Sep 05 2013

STATUS

approved

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Last modified September 25 19:18 EDT 2021. Contains 347659 sequences. (Running on oeis4.)