OFFSET
1,5
LINKS
Yichao Chen et al., On the genus distribution of wheels ..., Discrete Math., 341 (2018), 934-935.
FORMULA
Theorem 3.4 of Chen et al. (2018) gives a formula.
EXAMPLE
Triangle begins:
1,
1,1,
1,7,
1,29,18,
1,95,288,
1,275,2484,1080,
1,742,15589,29748,
...
MAPLE
s1 := proc(n, k)
(-1)^n*combinat[stirling1](n, k) ;
end proc:
A301731 := proc(n, k)
local a, m, i ;
a := 4*s1(n+1, k-1) ;
for m from 1 to n do
a := a+add( binomial(k+i, k) *binomial(n, m) *((n+1)^i-(n+1-m)^i-(m+1)^i+1) *s1(n+2, k+1+i), i=0..n+1-k) ;
end do:
a/n/(n+1) ;
abs(%/2) ;
end proc:
for n from 1 to 15 do
for k from n+1 to 1 by -2 do
printf("%a, ", A301731(n, k)) ;
end do:
printf("\n") ;
end do: # R. J. Mathar, Apr 08 2018
CROSSREFS
KEYWORD
nonn,tabf
AUTHOR
N. J. A. Sloane, Apr 03 2018
STATUS
approved