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Number of primes of form 4k+1 between n^2 and (n+1)^2.
8

%I #11 Oct 06 2021 21:24:07

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

%T 5,4,5,4,3,7,7,3,7,5,6,5,8,8,5,4,8,9,6,5,7,7,6,8,7,8,7,6,8,7,9,8,7,7,

%U 8,9,5,10,8,7,11,9,6,10,12,8,10,10,7,8,10,12,10,11,11,9,10,10,11,10,11,11

%N Number of primes of form 4k+1 between n^2 and (n+1)^2.

%C Related to Legendre's conjecture that there is always a prime between two consecutive squares.

%H Seiichi Manyama, <a href="/A077766/b077766.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from T. D. Noe)

%e a(8)=1 because the prime 73 is between squares 64 and 81.

%t maxN=100; a=Table[0, {maxN}]; maxP=PrimePi[(maxN+1)^2]; For[i=1, i<=maxP, i++, p=Prime[i]; If[Mod[p, 4]==1, j=Floor[Sqrt[p]]; a[[j]]++ ]]; a

%Y Cf. A002144, A014085, A077767.

%K nonn

%O 1,6

%A _T. D. Noe_, Nov 20 2002