a(n) = n(n-1)(n-3)(n-6)...(n-t), where t is the largest triangular number less than n; number of factors in the product is ceiling((sqrt(1+8*n)-1)/2).

A094261

a(n) = n(n-1)(n-3)(n-6)...(n-t), where t is the largest triangular number less than n; number of factors in the product is ceiling((sqrt(1+8*n)-1)/2).

Terms

    a(0) =1a(1) =2a(2) =6a(3) =12a(4) =40a(5) =90a(6) =168a(7) =560a(8) =1296a(9) =2520a(10) =4400a(11) =14256a(12) =32760a(13) =64064a(14) =113400a(15) =187200a(16) =586432a(17) =1321920a(18) =2560896a(19) =4522000a(20) =7484400a(21) =11797632a(22) =35784320a(23) =78871968a(24) =150480000a(25) =263120000a(26) =433060992a(27) =681080400a(28) =1033305728a(29) =3044304000

External references