cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A080046 Multiplicative Pascal triangle, read by rows: T(n,1)=T(n,n)=n and T(n,k) = T(n-1,k-1) * T(n-1,k).

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%I A080046 #18 Dec 15 2015 00:58:09
%S A080046 1,2,2,3,4,3,4,12,12,4,5,48,144,48,5,6,240,6912,6912,240,6,7,1440,
%T A080046 1658880,47775744,1658880,1440,7,8,10080,2388787200,79254226206720,
%U A080046 79254226206720,2388787200,10080,8,9,80640,24078974976000
%N A080046 Multiplicative Pascal triangle, read by rows: T(n,1)=T(n,n)=n and T(n,k) = T(n-1,k-1) * T(n-1,k).
%C A080046 T(n,2) = A052849(n) for n>1.
%H A080046 Reinhard Zumkeller and Andre F. Labossiere, <a href="/A080046/b080046.txt">Rows n=1..14 of triangle, flattened</a>
%H A080046 <a href="/index/Pas#Pascal">Index entries for triangles and arrays related to Pascal's triangle</a>
%e A080046 1
%e A080046 2  2
%e A080046 3  4  3
%e A080046 4 12 12 4
%o A080046 (Haskell)
%o A080046 a080046 n k = a080046_tabl !! (n-1) !! (k-1)
%o A080046 a080046_row n = a080046_tabl !! (n-1)
%o A080046 a080046_tabl = iterate f [1] where
%o A080046    f (x:xs) = [x + 1] ++ (zipWith (*) xs $ reverse xs) ++ [x + 1]
%o A080046 -- _Reinhard Zumkeller_, Oct 27 2013
%Y A080046 Cf. A007318, A082611.
%Y A080046 Cf. A051597.
%K A080046 nonn,tabl,look
%O A080046 1,2
%A A080046 _Reinhard Zumkeller_, Jan 21 2003
%E A080046 Corrected by _André F. Labossière_, Sep 27 2004