A285181 Index m such that A280864(m) = n^2.

1, 3, 10, 13, 35, 33, 48, 65, 94, 100, 86, 142, 144, 157, 148, 258, 399, 300, 453, 395, 319, 483, 358, 565, 720, 665, 845, 755, 893, 864, 924, 1009, 1033, 1133, 1216, 1262, 1293, 1437, 1375, 1603, 1724, 1720, 2015, 1898, 2154, 2078, 2071, 2257, 2547, 2422, 2687, 2618, 2714, 2807, 3055, 3034

Offset

1,2

Links

Michael De Vlieger, Table of n, a(n) for n = 1..4107 (first 996 terms from N. J. A. Sloane).

Maple

# Let b280864 contain a list of the terms of A280864
a:=[];
for n from 1 to 500 do
if member(n^2, b280864, 'p') then a:=[op(a), p]; else  \
lprint("error", n); break; fi; od:
a;

Mathematica

nn = 3600; c[_] := False; m[_] := 1;
Set[{i, j, s, t, c[1], c[2]}, {1, 2, {}, {2}, True, True}];
s = Sort[{{1, 1}}~Join~Reap[Do[
  r = Times @@ Select[t, FreeQ[s, #] &];
  v = Times @@ Intersection[s, t];
  k = m[r]; While[Or[c[#], ! CoprimeQ[v, #]] &[k*r], k++]; k *= r;
  Set[{c[k], i, j, s, t}, {True, j, k, t, FactorInteger[k][[All, 1]]}];
  If[k == u, While[c[u], u++]]; While[c[r*m[r]], m[r]++];
  If[IntegerQ@ Sqrt[k], Sow[{Sqrt[k], n}]], {n, 3, nn}] ][[-1, 1]] ];
s[[;; #, -1]] &@ LengthWhile[Differences@ s[[;; , 1]], # == 1 &] (* Michael De Vlieger, Apr 11 2025 *)

Crossrefs

Cf. A280864.

Sequence in context: A042897 A041169 A068361 * A042331 A082975 A275432

Adjacent sequences: A285178 A285179 A285180 * A285182 A285183 A285184

Keyword

nonn

Author

N. J. A. Sloane, Apr 14 2017

Status

approved