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A081141
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11th binomial transform of (0,0,1,0,0,0,...).
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14
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0, 0, 1, 33, 726, 13310, 219615, 3382071, 49603708, 701538156, 9646149645, 129687123005, 1711870023666, 22254310307658, 285596982281611, 3624884775112755, 45569980029988920, 568105751040528536
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OFFSET
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0,4
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COMMENTS
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Starting at 1, the three-fold convolution of A001020 (powers of 11).
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LINKS
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FORMULA
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a(n) = 33*a(n-1) - 363*a(n-2) + 1331*a(n-3), a(0) = a(1) = 0, a(2) = 1.
a(n) = 11^(n-2)*binomial(n, 2).
G.f.: x^2/(1 - 11*x)^3.
Sum_{n>=2} 1/a(n) = 22 - 220*log(11/10).
Sum_{n>=2} (-1)^n/a(n) = 264*log(12/11) - 22. (End)
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MAPLE
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seq((11)^(n-2)*binomial(n, 2), n=0..30); # G. C. Greubel, May 13 2021
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MATHEMATICA
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LinearRecurrence[{33, -363, 1331}, {0, 0, 1}, 30] (* Harvey P. Dale, Dec 15 2014 *)
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PROG
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(PARI) vector(20, n, n--; 11^(n-2)*binomial(n, 2)) \\ G. C. Greubel, Nov 23 2018
(Sage) [11^(n-2)*binomial(n, 2) for n in range(20)] # G. C. Greubel, Nov 23 2018
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CROSSREFS
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Sequences similar to the form q^(n-2)*binomial(n, 2): A000217 (q=1), A001788 (q=2), A027472 (q=3), A038845 (q=4), A081135 (q=5), A081136 (q=6), A027474 (q=7), A081138 (q=8), A081139 (q=9), A081140 (q=10), this sequence (q=11), A081142 (q=12), A027476 (q=15).
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KEYWORD
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easy,nonn
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AUTHOR
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STATUS
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approved
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