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A123028
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a(n) = (3*n^2-3*n+1)*a(n-2), n>2.
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0
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1, 1, 19, 37, 1159, 3367, 147193, 569023, 31940881, 154205233, 10572431611, 61219477501, 4958470425559, 33487054193047, 3128794838527729, 24144166073186887, 2556225383077154593, 22188488621258749153
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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FORMULA
| a(n) = A003215(n-1) *a(n-2), n>2.
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MATHEMATICA
| f[n_Integer] = Module[{a}, a[n] /. RSolve[{a[n] == 2*a[n - 1] - a[n - 2] + 6, a[0] == 1, a[1] == 7}, a[n], n][[1]] // FullSimplify] ; Clear[a] a[n_] := a[n] = f[n]*a[n - 2]/(n*(n - 1)); a[0] = 1; a[1] = 1; Table[ExpandAll[a[n]*n! ], {n, 0, 30}]
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CROSSREFS
| Cf. A003215.
Sequence in context: A136063 A111441 A144594 * A067205 A196185 A040342
Adjacent sequences: A123025 A123026 A123027 * A123029 A123030 A123031
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KEYWORD
| nonn,easy
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AUTHOR
| Roger Bagula (rlbagulatftn(AT)yahoo.com), Sep 25 2006
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EXTENSIONS
| Definition replaced by recurrence - the Assoc. Eds. of the OEIS, Mar 27 2010
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