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 A077553 Triangle in which the n-th row contains n distinct composite numbers with the least product and has least number of prime divisors. No member of a row is a multiple of another member of the row. 4
 4, 4, 6, 4, 6, 9, 4, 6, 9, 10, 4, 6, 9, 10, 15, 4, 6, 9, 10, 15, 25, 4, 6, 9, 10, 14, 15, 21, 4, 6, 9, 10, 14, 15, 21, 25, 4, 6, 9, 10, 14, 15, 21, 25, 35, 4, 6, 9, 10, 14, 15, 21, 25, 35, 49, 4, 6, 9, 10, 14, 15, 21, 22, 25, 33, 35, 4, 6, 9, 10, 14, 15, 21, 22, 25, 33, 35, 49, 4, 6, 9, 10 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS If there are two sets of distinct composite numbers satisfying the above condition then the set with lesser product is chosen irrespective of the number of prime divisors. Perhaps the ambiguity may not arise. E.g. Row 6 is 4,6,9,10,15,25. This row can not be extended to get the next row without bringing in another prime because every number divisible by 2,3 or 5 will be a multiple of one of the previous terms. Hence in row 7, prime 7 has to be brought in and then we get a new set of numbers 4,6,9,10,14,15,21. LINKS Tanya Khovanova, Recursive Sequences EXAMPLE 4; 4,6; 4,6,9; 4,6,9,10; 4,6,9,10,15; 4,6,9,10,15,25; 4,6,9,10,14,15,21; CROSSREFS Cf. A001358, A077554, A077555, A087112, A005843. Sequence in context: A059656 A205373 A064041 * A010659 A131089 A204068 Adjacent sequences:  A077550 A077551 A077552 * A077554 A077555 A077556 KEYWORD nonn,tabl AUTHOR Amarnath Murthy (amarnath_murthy(AT)yahoo.com), Nov 10 2002 EXTENSIONS More terms from Ray Chandler, Aug 21 2003 STATUS approved

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