A302940 Lexicographically first sequence of distinct terms such that the product of any two terms is not a term of the sequence, and the product of any two digits is not a digit of the sequence.
2, 3, 4, 5, 7, 9, 44, 47, 49, 54, 55, 57, 59, 74, 75, 77, 79, 95, 97, 99, 444, 445, 447, 449, 454, 455, 457, 459, 474, 477, 479, 494, 497, 499, 544, 545, 547, 549, 554, 555, 557, 559, 574, 575, 577, 579, 594, 595, 597, 599, 744, 745, 747, 749, 754, 755, 757, 759, 774, 775, 777, 779, 794, 795, 797, 799
Offset: 1
Examples
2 x 3 = 6 and there is no term or digit 6 in the sequence; 2 x 4 = 8 and there is no term or digit 8 in the sequence; 2 x 5 = 10 and there is no term 10 in the sequence; 2 x 6 = 12 and there is no term 12 in the sequence; 2 x 7 = 14 and there is no term 14 in the sequence; 2 x 9 = 18 and there is no term 18 in the sequence; 3 x 4 = 12 and there is no term 12 in the sequence; 3 x 5 = 15 and there is no term 15 in the sequence; etc.
Links
- Jean-Marc Falcoz, Table of n, a(n) for n = 1..1002
Crossrefs
Cf. A302938 where the word “product” is replaced by “sum”.
Comments