login
The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 

Logo


Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A144270 Lower triangular array called S2hat(-1) related to partition number array A144269. 6

%I

%S 1,1,1,3,1,1,15,4,1,1,105,18,4,1,1,945,129,19,4,1,1,10395,1095,132,19,

%T 4,1,1,135135,11880,1119,133,19,4,1,1,2027025,149940,12057,1122,133,

%U 19,4,1,1,34459425,2218545,151560,12081,1123,133,19,4,1,1

%N Lower triangular array called S2hat(-1) related to partition number array A144269.

%C If in the partition array M32hat(-1)=A144269 entries with the same parts number m are summed one obtains this triangle of numbers S2hat(-1). In the same way the Stirling2 triangle A008277 is obtained from the partition array M_3 = A036040.

%C The first three columns are A001147, A144272, A144273.

%H W. Lang, <a href="/A144270/a144270.txt">First 10 rows of the array and more.</a>

%H W. Lang, <a href="http://www.cs.uwaterloo.ca/journals/JIS/VOL12/Lang/lang.html">Combinatorial Interpretation of Generalized Stirling Numbers</a>, J. Int. Seqs. Vol. 12 (2009) 09.3.3.

%F a(n,m)=sum(product(|S2(-1;j,1)|^e(n,m,q,j),j=1..n),q=1..p(n,m)) if n>=m>=1, else 0. Here p(n,m)=A008284(n,m), the number of m parts partitions of n and e(n,m,q,j) is the exponent of j in the q-th m part partition of n. |S2(-1;j,1)|= A001497(j-1,0) = A001147(j-1) = (2*j-3)(!^2) (2-factorials) for j>=2 and 1 if j=1.

%e [1];[1,1];[3,1,1];[15,4,1,1];[105,18,4,1,1];...

%Y Row sums A144271.

%K nonn,easy,tabl

%O 1,4

%A _Wolfdieter Lang_ Oct 09 2008

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified September 21 19:57 EDT 2020. Contains 337273 sequences. (Running on oeis4.)