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A374854
a(n) = (1/30)*A028361(n) for n>=3.
0
1, 9, 153, 5049, 328185, 42335865, 10880317305, 5581602777465, 5721142846901625, 11722621693301429625, 48027581077455957173625, 393489971767596657123509625, 6447333187412071226968705205625, 211272661218306162036537500883125625
OFFSET
3,2
COMMENTS
a(n+1)/a(n) is an integer for n>=0, so (a(n)) is a divisibility sequence.
FORMULA
a(n) = (1/30)(s**t)(n), where s = A000012 = (1,1,1,...), t = A000079 = (1,2,4,8,16,...), and ** denotes obverse convolution, as in A374848.
a(n) = A060202(n+1)/180. - Hugo Pfoertner, Aug 07 2024
MATHEMATICA
s[n_] := 1; t[n_] := 2^n;
u[n_] := Product[s[k] + t[n - k], {k, 0, n}]
(1/30) Table[u[n], {n, 2, 20}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Clark Kimberling, Aug 05 2024
STATUS
approved