A113426 - OEIS

%I #10 Mar 10 2017 21:40:04

%S 2,5,11,17,23,37,47,67,83,101,127,149,167,197,227,257,293,331,359,401,

%T 443,487,523,577,631,677,727,787,839,907,967,1021,1091,1153,1223,1297,

%U 1367,1447,1523,1601,1693,1759,1847,1933,2027,2113,2207,2309,2399,2503

%N Greatest prime closest to n^2.

%C A060272(n) = abs(A000290(n) - a(n));

%C A113425(n) <= a(n).

%H G. C. Greubel, <a href="/A113426/b113426.txt">Table of n, a(n) for n = 1..1000</a>

%t f[n_]:=Module[{n2=n^2,np1,np2},np1=NextPrime[n2,-1];np2=NextPrime[n2];If[(n2-np1)<(np2-n2),np1,np2]]

%t Table[f[i],{i,50}]

%K nonn

%O 1,1

%A _Reinhard Zumkeller_, Oct 31 2005