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A375489
Omit the trailing zeros from double factorial of even numbers (A000165).
0
1, 2, 8, 48, 384, 384, 4608, 64512, 1032192, 18579456, 37158912, 817496064, 19619905536, 510117543936, 14283291230208, 42849873690624, 1371195958099968, 46620662575398912, 1678343852714360832, 63777066403145711616, 255108265612582846464, 10714547155728479551488
OFFSET
0,2
FORMULA
a(n) = A000165(n)/10^A027868(n).
a(n) = a(n-1)*(2*n)/10^A122840(2*n) for n > 0.
MATHEMATICA
a[n_]:=2^n*n!/10^IntegerExponent[n!, 10]; Array[a, 22, 0]
KEYWORD
nonn,base,easy
AUTHOR
Stefano Spezia, Aug 18 2024
STATUS
approved