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Numbers k such that k*(k+7) gives the concatenation of two numbers m and m+9.
4

%I #6 Jul 16 2021 21:34:02

%S 27,67,3416102887775247376839416334668636,

%T 3756559953325598880263233435801765,4313503800489302411917772257282209

%N Numbers k such that k*(k+7) gives the concatenation of two numbers m and m+9.

%e 67 * 74 = 49//58, where // denotes concatenation.

%Y Cf. A116169, A116346, A116352, A116354.

%K nonn,base

%O 1,1

%A _Giovanni Resta_, Feb 06 2006