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%I #7 Jul 18 2021 02:55:29
%S 2,5,43,54,38161,61836,83616,346978,653019,950049,8647553,9534263,
%T 8167822281,9007920990,9209900790,9950000499,4737445289219,
%U 4990568257185,5009431742812,5262554710778,8373808925583
%N Numbers k such that k*(k+4) gives the concatenation of two numbers m and m+1.
%Y Cf. A115428, A116288, A116296, A116298, A116317.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Feb 06 2006