David Wilson wrote: << I took a look at Ulam(1,2), the Ulam sequence starting with (1, 2) and including every subsequent number which is a unique sum of distinct earlier terms. This is Sloane's A002858.
Actually A002858 is described in EIS as "Ulam numbers: next is uniquely the sum of 2 earlier terms" It's listed in EIS as beginning 1,2,3,4,6,8,11,13,..., (least such) but one could get a whole nother sequence via 1,2,3,5,8,13,21,34,..., (largest such) or 1,2,3,5,4,9,8,17,..., (largest alternating with least) for instance. ------------------------------------------------------------------------------ --------------- To well-define A002858 perhaps one should define it as "[Sequence beginning with 1,2 whose] next term is *the least* unique sum of 2 previous terms" QUESTION: If "2 previous terms" were replaced with "any number of previous terms" in this definition, would it be a different sequence? --Dan A.