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A143850 Numbers of the form (p^2 + q^2)/2, for odd primes p and q. 5
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 (list; graph; refs; listen; history; text; internal format)
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
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. A075892 (a subsequence).
Sequence in context: A073160 A242987 A346146 * A017077 A004768 A226323
KEYWORD
nonn
AUTHOR
T. D. Noe, Sep 03 2008
STATUS
approved

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Last modified May 30 15:08 EDT 2024. Contains 372968 sequences. (Running on oeis4.)