A113797 - OEIS

A113797

Numbers k whose digits can be divided into two contiguous parts, k = concatenate(x, y), such that k = |x^2 - y^2|.

%I #14 Jul 27 2021 07:36:18

%S 48,100,147,3468,10000,10101,13467,16128,34188,140400,190476,216513,

%T 300625,334668,416768,484848,530901,1000000,1010100,1016127,1034187,

%U 1140399,1190475,1216512,1300624,1334667,1416767,1484847,1530900

%N Numbers k whose digits can be divided into two contiguous parts, k = concatenate(x, y), such that k = |x^2 - y^2|.

%e 3468 = |34^2 - 68^2|.

%t lst = {}; Do[p = 10; While[n > p, If[Abs[Mod[n, p]^2 - Floor[n/p]^2] == n, AppendTo[lst, n]]; p*=10], {n, 10^6}]; lst

%K base,nonn

%O 1,1

%A _Giovanni Resta_, Jan 21 2006