cp's OEIS Frontend

A116320 n times n+8 gives the concatenation of two numbers m and m+4.

%I A116320 #9 Jun 21 2018 03:03:03
%S A116320 4,86,32762,67231,76322,693956,900097,7295105,9068525,3664355432,
%T A116320 6335644561,8015841979,8419801579,9900000997,3252382148828,
%U A116320 6747617851165,7253863787097,9474890578438,9981136514370
%N A116320 n times n+8 gives the concatenation of two numbers m and m+4.
%C A116320 Includes 10^(4*k+2)-10^(3*k+2)+10^(k+1)-3 for k >= 1. - _Robert Israel_, Jun 20 2018
%H A116320 Robert Israel, <a href="/A116320/b116320.txt">Table of n, a(n) for n = 1..2282</a>
%p A116320 Res:= NULL: count:= 0:
%p A116320 for d from 1 while count < 100 do
%p A116320   R:= sort(select(t -> t^2 + 8*t - 4 > 10^(2*d-1) and t^2+8*t-4 < 10^(2*d), map(t -> rhs(op(t)), [msolve(n^2+8*n-4, 10^d+1)])));
%p A116320   count := count+nops(R);
%p A116320   Res:= Res, op(R);
%p A116320 od:
%p A116320 Res; # _Robert Israel_, Jun 20 2018
%Y A116320 Cf. A116189, A116312, A116319, A116321, A116327.
%K A116320 nonn,base,look
%O A116320 1,1
%A A116320 _Giovanni Resta_, Feb 06 2006