%I #11 Apr 05 2017 00:32:24

%S 30,12834,18141477989940702510,48095105831852088000,

%T 5437693915503684117819750,5784962279163039331595016,

%U 864479870564593025822726220,24351951618610295127241673897127630,25652594148194488759500411647073225254466

%N Numbers whose squares remain squares when prepended with 9 and appended with 25 in base 10.

%e 30^2 = 900, 990025 = 995^2.

%p F:= proc(d) local m, D,P;

%p m:= 9*10^d+25;

%p D:= numtheory:-divisors(m);

%p P:= map(t -> (m/t - t)/20, select(t -> t^2 < m and (m/t - t) mod 20 = 0, D));

%p op(select(t -> 10^(d-3) <= t^2 and t^2 < 10^(d-2),P));

%p end proc:

%p seq(F(n),n=4..83); # _Robert Israel_, Apr 04 2017

%Y Cf. A249621, A249968, A249969, A249970, A249971, A249972, A250433, A250434.

%K nonn,base,more

%O 1,1

%A _Chai Wah Wu_, Nov 23 2014