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Beginning with a(1)=0, take a(n) to be the smallest number not equal to the product of two consecutive (not distinct) earlier terms.
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%I #8 Jun 21 2021 06:24:02

%S 0,0,1,1,2,2,3,3,5,5,7,7,8,8,10,10,11,11,12,12,13,13,14,14,16,16,17,

%T 17,18,18,19,19,20,20,21,21,22,22,23,23,24,24,26,26,27,27,28,28,29,29,

%U 30,30,31,31,32,32,33,33,34,34,36,36,37,37,38,38,39,39,40,40,41,41,42,42

%N Beginning with a(1)=0, take a(n) to be the smallest number not equal to the product of two consecutive (not distinct) earlier terms.

%C Apparently the definition is: a(1)=0. For even n, a(n)=a(n-1). For odd n, a(n) is the smallest value > a(n-1) which is not equal to some product a(i)*a(i-1) of two consecutive earlier terms. - _R. J. Mathar_, Jun 21 2021

%Y Cf. A121229.

%K easy,nonn

%O 1,5

%A _Giovanni Teofilatto_, Aug 23 2006

%E Offset corrected. - _R. J. Mathar_, Jun 20 2021