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A117054 Number of ordered ways of writing n = i + j, where i is a prime and j is of the form k*(k+1), k > 0. 2

%I #14 Feb 27 2020 22:17:15

%S 0,0,0,1,1,0,1,1,2,0,1,0,2,1,2,0,2,0,3,0,1,1,3,0,4,0,1,0,2,0,3,1,3,0,

%T 3,0,3,0,2,0,2,0,5,1,2,0,3,0,6,0,1,0,4,0,3,0,1,1,5,0,5,0,3,0,3,0,4,0,

%U 2,0,3,0,7,1,3,0,3,0,6,0,2,0,4,0,6,0,2,0,4,0,5,1,3,0,5,0,3,0,3,0,5,0,8,0,1

%N Number of ordered ways of writing n = i + j, where i is a prime and j is of the form k*(k+1), k > 0.

%C Based on a posting by _Zhi-Wei Sun_ to the Number Theory Mailing List, Mar 23 2008, where he conjectures that a(2n+1) > 0 for n >= 2.

%C _Zhi-Wei Sun_ has offered a monetary reward for settling this conjecture.

%C No counterexample below 10^10. - _D. S. McNeil_

%H Zhi-Wei Sun, <a href="http://listserv.nodak.edu/cgi-bin/wa.exe?A1=ind0803&amp;L=nmbrthry">Posing to Number Theory List (1)</a>

%H Zhi-Wei Sun, <a href="https://listserv.nodak.edu/cgi-bin/wa.exe?A2=NMBRTHRY;9ebd2e77.0803">Posting to Number Theory List (2)</a>

%H Zhi-Wei Sun, <a href="http://arXiv.org/abs/0803.3737">Conjectures on sums of primes and triangular numbers</a>, arxiv:0803.3737 and Journal of Combinatorics and Number Theory, 1 (2009), no.1, 65-76

%p t0:=array(0..300); for n from 0 to 300 do t0[n]:=0; od:

%p t1:=[seq(ithprime(i),i=1..70)]; t2:=[seq(n*(n+1),n=1..30)];

%p for i from 1 to 70 do for j from 1 to 30 do k:=t1[i]+t2[j]; if k <= 300 then t0[k]:=t0[k]+1; fi; od: od:

%p t3:=[seq(t0[n],n=1..300)];

%Y Cf. A132399, A144590.

%K nonn,easy

%O 0,9

%A _N. J. A. Sloane_, Jan 15 2009

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Last modified March 29 00:26 EDT 2024. Contains 371264 sequences. (Running on oeis4.)