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a(n) is the smallest composite number having the same base-n digits (both type and quantity) as its prime factors (with multiplicity).
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%I #5 Jan 20 2017 20:01:39

%S 159,7847,1135,83494,57,30057,85,72646,1255,18193,185,101212405,4119,

%T 63791,88357,31054582,489,4196517,451,4598494,13315,1012985,679,

%U 7009758597,26533,2884373,985,646372334,1057,989775393,1285,1395750166,179503,73294351,1387

%N a(n) is the smallest composite number having the same base-n digits (both type and quantity) as its prime factors (with multiplicity).

%C A278981(n) <= A281336(n)

%e In base 2: The digits of 159 (10011111) are the same type and quantity as the total of those in its prime factors, 3 (11) and 53 (110101); 2 zeros, 6 ones.

%e In base 26: The digits of 26533 (1,13,6,13) are the same type and quantity as the total of those in its prime factors, 13 (13), 13 (13), and 157 (6,1); 1 one, 1 six, 2 thirteens.

%Y Cf. A278981, A280928, A281335.

%K nonn,base

%O 2,1

%A _Hans Havermann_, Jan 20 2017