

A109367


Squares of the form 2*p + 3, where p is a prime.


3



9, 25, 49, 121, 169, 361, 529, 625, 841, 961, 1369, 1681, 2209, 3025, 4225, 4489, 5329, 5929, 6241, 8281, 9409, 10201, 10609, 11881, 14161, 20449, 22801, 24025, 24649, 25921, 34969, 38809, 42025, 43681, 44521, 48841, 51529, 54289, 55225, 57121
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OFFSET

1,1


COMMENTS

The first seven terms are primes squared: 3^2, 5^2, 7^2, 11^2, 13^2, 17^2, 19^2, 23^2.


LINKS

Charles R Greathouse IV, Table of n, a(n) for n = 1..10000


FORMULA

a(n) = A109358(n)^2 = 2*A098828(n) + 3.


MATHEMATICA

Select[Table[(2Prime[n] + 3)^(1/2), {n, 3500}], IntegerQ]^2 (* Ray Chandler, Aug 25 2005 *)
Select[2*Prime[Range[3500]]+3, IntegerQ[Sqrt[#]]&] (* Harvey P. Dale, Sep 07 2020 *)


PROG

(PARI) is(n)=issquare(n) && n%2 && isprime(n\21) \\ Charles R Greathouse IV, Aug 06 2013


CROSSREFS

Cf. A098828, A109358.
Sequence in context: A339126 A176970 A110284 * A110588 A282631 A245694
Adjacent sequences: A109364 A109365 A109366 * A109368 A109369 A109370


KEYWORD

nonn


AUTHOR

Giovanni Teofilatto, Aug 23 2005


EXTENSIONS

Extended by Ray Chandler and Robert G. Wilson v, Aug 25 2005


STATUS

approved



