A100372 Build up the least positive nonprime number from all subsets of decimal digits {0,1,2,3,4,5,6,7,8,9}. The terms are ordered as follows: 1. for fixed k, the k-digit-subsets for design are ordered lexicographically; 2. choose k=1,2,...,9,10-subsets.

1, 22, 33, 4, 55, 6, 77, 8, 9, 10, 20, 30, 40, 50, 60, 70, 80, 90, 12, 133, 14, 15, 16, 117, 18, 91, 32, 24, 25, 26, 27, 28, 92, 34, 35, 36, 377, 38, 39, 45, 46, 74, 48, 49, 56, 57, 58, 95, 76, 68, 69, 78, 779, 98, 102, 130, 104, 105, 106, 170, 108, 190, 203, 204, 205, 206

Offset: 1

Author

Labos Elemer, Dec 01 2004

Keywords

• fini
• nonn
• base

Comments

Composite analog of A099756. From the 1023 nonempty digit subsets 1022 terms can be designed because 0 is not permitted.

Examples

			For 2-subsets of {1,3},{1,7},{3,7},{7,9} the least composites should have at least two copies of a digit; that is why the solutions {133,117,377,779} have 3 digits.
		

Crossrefs

Cf. A099756.

Programs

Mathematica

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