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A093910 Product of n-th row of irregular triangle defined in A093911. 3

%I #16 Dec 15 2016 12:23:20

%S 1,6,120,5040,5765760,19275223968000,13644281345408020027550269440000,

%T 4402827357584746886229433170489943024971625310770489684257669120000000000

%N Product of n-th row of irregular triangle defined in A093911.

%C Next term has 168 digits.

%H Michael De Vlieger, <a href="/A093910/b093910.txt">Table of n, a(n) for n = 1..11</a> (Term 11 has 824 decimal digits.)

%F For n > 1, a(n) = prod_{i = A093911(n)..A093911(n+1)-1} i.

%e a(3) = 120 because a(1) is the product of 1 successive numbers starting with 1 = 1, and a(2) is the product of 2 successive numbers (2,3) = 6 and a(3) is the product of 3 successive numbers (4,5,6) = 120. All the products have the property that a(n) = 0 (mod a(n - 1)). Thus a(3) = 120.

%t a = {{1, 1}, {2, 2}}; Do[k = Last@ a[[i - 1]]; While[! Divisible[Pochhammer[Total@ a[[i - 1]], k], Pochhammer @@ a[[i - 1]]], k++]; AppendTo[a, {Total@ a[[i - 1]], k}], {i, 3, 8}]; Pochhammer @@ # & /@ a (* _Michael De Vlieger_, Dec 15 2016 *)

%Y Cf. A090904, A093911.

%K nonn,easy,less

%O 1,2

%A _Amarnath Murthy_, Apr 24 2004

%E Edited and extended by _David Wasserman_, Mar 27 2006

%E New name from _Ivan Neretin_, Dec 15 2016

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Last modified April 24 18:17 EDT 2024. Contains 371962 sequences. (Running on oeis4.)