A143850 Numbers of the form (p^2 + q^2)/2, for odd primes p and q.

9, 17, 25, 29, 37, 49, 65, 73, 85, 89, 97, 109, 121, 145, 149, 157, 169, 185, 193, 205, 229, 241, 265, 269, 277, 289, 325, 349, 361, 409, 425, 433, 445, 481, 485, 493, 505, 529, 541, 565, 601, 625, 661, 685, 689, 697, 709, 745, 769, 829, 841, 845, 853, 865

Offset

1,1

Comments

The primes in this sequence are listed in A103739.

a(n) mod 4 = 1. See A227697 for related sequence. - Richard R. Forberg, Sep 22 2013

The squares of primes in this sequence form the subsequence A001248 \ {4}. - Bernard Schott, Jul 09 2022

Links

T. D. Noe, Table of n, a(n) for n = 1..1000

Mathematica

Take[Union[Total[#]/2&/@(Tuples[Prime[Range[2, 20]], 2]^2)], 60] (* Harvey P. Dale, Dec 28 2014 *)

Prog

(PARI) list(lim)=my(v=List(), p2); lim\=1; if(lim<9, lim=8); forprime(p=3, sqrtint(2*lim-9), p2=p^2; forprime(q=3, min(sqrtint(2*lim-p2), p), listput(v, (p2+q^2)/2))); Set(v) \\ Charles R Greathouse IV, Feb 14 2017

Crossrefs

Cf. A001248, A045636, A103739, A227697.

Cf. A075892 (a subsequence).

Sequence in context: A073160 A242987 A346146 * A017077 A004768 A226323

Adjacent sequences: A143847 A143848 A143849 * A143851 A143852 A143853

Keyword

nonn

Author

T. D. Noe, Sep 03 2008

Status

approved