A115555 - OEIS

%I #11 Jul 15 2021 09:11:27

%S 1836734693877551020408163265306122449,

%T 7346938775510204081632653061224489796,

%U 15311909262759924385633270321361058601134215500945179584121,27221172022684310018903591682419659735349716446124763705104

%N Numbers k such that the concatenation of 9*k with k gives a square.

%Y Cf. A102567, A106497, A115527 - A115556.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Jan 25 2006