A062312 Nonprime numbers squared.

1, 16, 36, 64, 81, 100, 144, 196, 225, 256, 324, 400, 441, 484, 576, 625, 676, 729, 784, 900, 1024, 1089, 1156, 1225, 1296, 1444, 1521, 1600, 1764, 1936, 2025, 2116, 2304, 2401, 2500, 2601, 2704, 2916, 3025, 3136, 3249, 3364, 3600, 3844, 3969, 4096, 4225

Offset

1,2

Links

Harry J. Smith, Table of n, a(n) for n = 1..1000

Formula

a(n) = A018252(n)^2. - Omar E. Pol, Oct 30 2007

Sum_{n>=1} 1/a(n) = A275647. - Amiram Eldar, Oct 14 2020

Mathematica

Select[Range[100], !PrimeQ[#]&]^2 (* Harvey P. Dale, Jan 27 2016 *)

Prog

(PARI) for(n=1, 30, if(isprime(n), n+1, print(n^2)))
(PARI) n=0; for (m=1, 2000, if (!isprime(m), write("b062312.txt", n++, " ", m^2); if (n==1000, break))) \\ Harry J. Smith, Aug 04 2009
(PARI) is(n)=issquare(n, &n) && !isprime(n) \\ Charles R Greathouse IV, Sep 18 2015

Crossrefs

Cf. A002808, A018252, A275647.

Sequence in context: A253260 A144548 A161753 * A326709 A331139 A031360

Adjacent sequences: A062309 A062310 A062311 * A062313 A062314 A062315

Keyword

easy,nonn

Author

Jason Earls, Jul 05 2001

Extensions

More terms from Larry Reeves (larryr(AT)acm.org), Jul 05 2001

Status

approved