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A308866
a(n) = Sum_{k>=0} k^(2^n)/2^(k+1).
0
1, 3, 75, 545835, 5315654681981355, 23545154085734896649184490637144855476395, 1408419189834457368564204829523128565178390518208834734403870775971211916384631776000167564122146475
OFFSET
0,2
FORMULA
a(n) = Sum_{k=0..2^n} k!*Stirling2(2^n,k).
a(n) = A000670(A000079(n)).
MATHEMATICA
Table[Sum[k^(2^n)/2^(k + 1), {k, 0, Infinity}], {n, 0, 6}]
Table[Sum[k! StirlingS2[2^n, k], {k, 0, 2^n}], {n, 0, 6}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Ilya Gutkovskiy, Jun 29 2019
STATUS
approved