A394502 a(n) is the least positive integer k such that there are exactly n positive integers m where m^2 - k^2 is an anagram of k^2.

156, 336, 282, 1593, 1323, 4428, 3582, 1746, 4302, 10473, 11352, 10323, 18918, 3678, 32133, 15519, 11292, 31968, 32670, 29208, 19023, 34872, 13278, 32208, 32469, 32418, 34128, 35754, 50187, 101709, 100218, 95154, 91251, 100476, 51996, 32376, 104559, 101274, 40872, 91248, 101418, 66276, 85743

Offset

1,1

Comments

All terms are multiples of 3.

Links

Table of n, a(n) for n=1..43.

Example

a(3) = 282 because there are exactly 3 positive integers m where m^2 - 282^2 is an anagram of 282^2 = 79524, namely 354^2 - 282^2 = 45792, 357^2 - 282^2 = 47925, and 393^2 - 282^2 = 74925, and 282 is the least number that works.

Maple

N:= 50: # for a(1) .. a(N)
V:= Vector(N): count:= 0:
f:= proc(n) local L, t, m, k, r;
  L:= sort(convert(n^2, base, 10));
  m:= 10^ilog10(n^2);
  t:= 0;
  for k from ceil(sqrt(n^2+m)) to floor(sqrt(n^2+10*m)) by 3 do
    if sort(convert(k^2-n^2, base, 10)) = L then t:= t+1 fi
  od;
  t
end proc;
for n from 3 by 3 while count < N do
  v:= f(n);
  if v > 0 and v <= N and V[v] = 0 then count:= count+1; V[v]:= n fi
od:
convert(V, list);

Crossrefs

Cf. A393978, A393998, A394001.

Sequence in context: A166397 A065709 A037983 * A298909 A366172 A156849

Adjacent sequences: A394498 A394499 A394500 * A394503 A394504 A394506

Keyword

nonn,base

Author

Robert Israel, Mar 22 2026

Status

approved