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A110323
Diagonal sums of a number triangle related to the Jacobsthal numbers.
1
1, 1, 7, 32, 283, 2643, 32317, 443824, 7115461, 127222805, 2541399091, 55739417376, 1335729425647, 34666455314407, 969419191792633, 29046504524166368, 928541094344685577, 31540972026299055849
OFFSET
0,3
COMMENTS
Diagonal sums of number triangle A110321.
FORMULA
a(n)=sum{k=0..floor(n/2), (n-k)!*J(n-2k+1)/k!}, J(n)=A001045(n).
MATHEMATICA
J[n_] := (2^n-(-1)^n)/3; a[n_] := Sum[(n-k)!*J[n-2*k+1]/k!, {k, 0, n/2}]; Table[a[n], {n, 0, 17}] (* Jean-François Alcover, Oct 08 2016 *)
CROSSREFS
Sequence in context: A177766 A240390 A024093 * A288721 A324412 A373442
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Jul 20 2005
STATUS
approved