login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A342110 a(n) = Sum_{k=0..n} Stirling2(n,k) * Stirling2(n,n-k). 4
1, 0, 1, 6, 61, 770, 12160, 228382, 4989621, 124262532, 3475892685, 107901412520, 3681266754660, 136918473752216, 5513911474915116, 239034083286873630, 11098790133822288645, 549539910028075555016, 28903562131933534643851, 1609321474965547356327246 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,4
LINKS
FORMULA
a(n) ~ c * d^n * (n-1)!, where
d = A238258 = 3.0882773047417401791158400820254382768364448971420138767247...
c = 0.12826577250734152801558828593238744179869387423941684693208180123477...
MATHEMATICA
Table[Sum[StirlingS2[n, k]*StirlingS2[n, n-k], {k, 0, n}], {n, 0, 20}]
PROG
(PARI) a(n) = sum(k=0, n, stirling(n, k, 2)*stirling(n, n-k, 2)); \\ Michel Marcus, Feb 28 2021
(Magma) [(&+[StirlingSecond(n, k)*StirlingSecond(n, n-k): k in [0..n]]): n in [0..30]]; // G. C. Greubel, Jun 03 2021
(Sage) [sum( stirling_number2(n, k)*stirling_number2(n, n-k) for k in (0..n) ) for n in (0..30)] # G. C. Greubel, Jun 03 2021
CROSSREFS
Cf. A048993.
Sequence in context: A034659 A369509 A064088 * A191803 A259271 A047737
KEYWORD
nonn
AUTHOR
Vaclav Kotesovec, Feb 28 2021
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified June 22 08:18 EDT 2024. Contains 373567 sequences. (Running on oeis4.)