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%I #8 Jul 20 2021 23:43:53
%S 64,1876,3214,8776,17227120144584448354,19391087990479091186,
%T 21557280540171744040,23970390649400564404,26051259424903756364,
%U 28697643366269876506,31320461807899711990,34215988012600009664
%N Numbers k such that k concatenated with k-4 gives the product of two numbers which differ by 9.
%C Also numbers k such that k concatenated with k+4 gives the product of two numbers which differ by 7.
%C Since k*(10^j+1) + 4 = m*(m+7) iff k*(10^j+1) - 4 = m*(m+7) - 8 = (m-1)*(m+8) = M*(M+9) this is trivially the same sequence. - _N. J. A. Sloane_, Apr 11 2007
%e 8776//8772 = 9364 * 9373, where // denotes concatenation. Also 8776//8780 = 9365 * 9372.
%Y Cf. A116132, A116140, A116264.
%Y Cf. A116180, A116187, A116189, A116195, A116319.
%K nonn,base
%O 1,1
%A _Giovanni Resta_, Feb 06 2006
%E Edited by _N. J. A. Sloane_, Apr 11 2007
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