A085019 a(n) = A083752(A085018(n)).
393, 109, 132, 157, 481, 184, 213, 1048, 244, 577, 277, 1833, 312, 681
Offset: 1
Extensions
Edited and extended by Stefan Steinerberger, Jul 30 2007
This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
a(24)=157 because (4*157+3*24)(3*157+4*24)= 396900=630*630.
a083752 n = head [k | k <- [n+1..], a010052 (12*(k+n)^2 + k*n) == 1] -- Reinhard Zumkeller, Apr 06 2015
a:= proc(n) local k; for k from n+1
while not issqr((4*k+3*n)*(4*n+3*k)) do od; k
end:
seq(a(n), n=1..50); # Alois P. Heinz, Dec 13 2013
a[n_] := For[k = n + 1, True, k++, If[IntegerQ[Sqrt[(4k+3n)(4n+3k)]], Return[k]]]; Table[an = a[n]; Print[an]; an, {n, 1, 50}] (* Jean-François Alcover, Oct 31 2016 *)
a(n)=my(k=n+1); while(!issquare((4*k+3*n)*(4*n+3*k)), k++); k \\ Charles R Greathouse IV, Dec 13 2013
diff(v)=vector(#v-1,i,v[i+1]-v[i]) a(n)=my(v=select(k->issquare(12*Mod(k,n)^2),[0..n-1])); forstep(k=n+v[1], 393*n, diff(concat(v,n)), if(issquare((4*k+3*n)*(4*n+3*k)) && k>n, return(k))) \\ Charles R Greathouse IV, Dec 13 2013
a(n)=for(k=n+1, 109*n\4, if(issquare((4*k+3*n)*(4*n+3*k)), return(k))); 393*n \\ Charles R Greathouse IV, Jan 09 2014
def a(n):
k = n + 1
while not is_square((4*k+3*n)*(4*n+3*k)):
k += 1
return k
[a(n) for n in (1..44)] # Peter Luschny, Jun 25 2014
Reap[For[n = 1, n < 1000, n++, r = Reduce[x^2 + 6 x y - 3 y^2 == n, {x, y}, Integers]; If[r =!= False, If[AnyTrue[{x, y} /. {ToRules[r /. C[1] -> 0]}, CoprimeQ @@ # &], Sow[n]]]]][[2, 1]] (* Jean-François Alcover, Oct 31 2016 *)
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