# Greetings from The On-Line Encyclopedia of Integer Sequences! http://oeis.org/ Search: id:a276453 Showing 1-1 of 1 %I A276453 #18 Oct 24 2018 08:07:50 %S A276453 1,1,2,6,42,903,136052,881442036,2581196224947732, %T A276453 342795531574625708871288171, %U A276453 5732512385084161208637718426682572229606557631,5754497648510061274107897581706624823818534711463525598519384262130236399970112 %N A276453 a(n) = (a(n-1)+1)*(a(n-2)+1)*(a(n-3)+1)/a(n-4) with a(0) = a(1) = 1, a(2) = 2, a(3) = 6. %H A276453 Seiichi Manyama, Table of n, a(n) for n = 0..15 %F A276453 a(n) = A051786(n)*A051786(n+1)*A051786(n+2). %t A276453 RecurrenceTable[{a[n] == (a[n - 1] + 1) (a[n - 2] + 1) (a[n - 3] + 1)/a[n - 4], a[0] == 1, a[1] == 1, a[2] == 2, a[3] == 6}, a, {n, 0, 11}] (* _Michael De Vlieger_, Sep 03 2016 *) %o A276453 (Ruby) %o A276453 def A276453(n) %o A276453 a = [1, 1, 2, 6] %o A276453 ary = [1] %o A276453 while ary.size < n + 1 %o A276453 i = a[1..-1].inject(1){|s, i| s * (i + 1)} %o A276453 break if i % a[0] > 0 %o A276453 a = *a[1..-1], i / a[0] %o A276453 ary << a[0] %o A276453 end %o A276453 ary %o A276453 end %Y A276453 Cf. A051786, A101879, A276175. %K A276453 nonn %O A276453 0,3 %A A276453 _Seiichi Manyama_, Sep 03 2016 # Content is available under The OEIS End-User License Agreement: http://oeis.org/LICENSE