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Lucky numbers that are products of smaller lucky numbers.
2

%I #8 Jul 15 2023 06:36:02

%S 1,9,21,49,63,75,93,99,105,111,129,135,169,189,195,201,219,231,237,

%T 259,261,273,297,357,399,429,477,483,489,495,511,553,559,579,615,621,

%U 645,651,693,723,729,735,777,801,805,819,855,867,897,903,925,931,957,961

%N Lucky numbers that are products of smaller lucky numbers.

%e 1 is a term because it is a lucky number and equals the empty product.

%e 21 is a term because 21 = 3*7 and both 21 and the two factors 3 and 7 are lucky numbers.

%e 729 is a term because 729 = 9*9*9 and both 729 and 9 are lucky numbers. (This is the first term that requires more than two factors.)

%Y Cf. A000959, A363635, A363636.

%K nonn

%O 1,2

%A _Pontus von Brömssen_, Jun 19 2023