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A210647 Least nonnegative m such that k(n) + k(m) is prime, where k(n) = n*(n+1)^2/2. 2

%I

%S 0,1,22,2,142,1,2,10,22,1,34,10,2,37,46,6,10,1,6,46,46,1,10,106,6,1,

%T 58,2,22,7,2,58,94,3,22,10,2,1,22,2,10,16,6,82,118,4,82,10,18,1,10,2,

%U 22,1,2,10,10,4,22,58,2,19,10,2,46,1,10,70,82,3,22,34

%N Least nonnegative m such that k(n) + k(m) is prime, where k(n) = n*(n+1)^2/2.

%H Charles R Greathouse IV, <a href="/A210647/b210647.txt">Table of n, a(n) for n = 1..10000</a>

%t f[n_] := n (n + 1)^2/2; Table[k = 0; While[! PrimeQ[f[n] + f[k]], k++]; k, {n, 100}] (* _T. D. Noe_, Apr 03 2012 *)

%o (PARI) a(n)=my(K=n*(n+1)^2/2,m);while(!isprime(K+m*(m+1)^2/2),m++);m \\ _Charles R Greathouse IV_, Aug 03 2012

%Y Cf. A006002, A129634, A210646.

%K nonn

%O 1,3

%A _Gerasimov Sergey_, Mar 27 2012

%E Corrected by _R. J. Mathar_, Mar 31 2012

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Last modified August 3 22:03 EDT 2021. Contains 346441 sequences. (Running on oeis4.)