A261713 Natural numbers that can be split into two squares, leading zeros allowed.

10, 11, 14, 19, 40, 41, 44, 49, 90, 91, 94, 99, 100, 101, 104, 109, 116, 125, 136, 149, 160, 161, 164, 169, 181, 250, 251, 254, 259, 360, 361, 364, 369, 400, 401, 404, 409, 416, 425, 436, 449, 464, 481, 490, 491, 494, 499, 640, 641, 644, 649, 810, 811, 814

Offset: 1

Author

Giovanni Teofilatto, Aug 29 2015

Keywords

• nonn
• base
• easy

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A046030, A053061, A168042, A191933.

Programs

Maple

a:= proc(n) option remember; local d, i, k;
      for k from 1+`if`(n=1, 1, a(n-1))
      do for i to length(k)-1 do
           if issqr(iquo(k, 10^i, 'd')) and
              issqr(d) then return k fi
         od
      od
    end:
seq(a(n), n=1..60);  # Alois P. Heinz, Aug 29 2015

Mathematica

qQ[n_] := Floor[ Sqrt@ n]^2 == n; ok[n_] := Catch[ Do[ If[ qQ@ Floor[n / 10^k] && qQ@ Mod[n, 10^k],Throw@ True], {k, IntegerLength[n] -1}]; False]; Select[Range@ 1000, ok] (* Giovanni Resta, Aug 29 2015 *)

Extensions

Name clarified by Zak Seidov, Aug 29 2015