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A075770
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Let u(1)=u(2)=u(3)=1, u(n+3)=(n*u(n)+(n+1)*u(n+1)+(n+2)*u(n+2))/(n+3); sequence gives values of n such that u(n) is an integer.
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1
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1, 2, 3, 10, 14, 350, 702, 817, 1053, 1405, 31426, 44770, 86766, 120118, 216918, 284310, 343278, 347646, 426465, 511758, 767637, 1005030, 1282398, 1483326, 1610510, 1930666, 2434318, 2643990, 2883465, 3345210, 3367430, 3420670, 3647278
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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MATHEMATICA
| a[1] = a[2] = a[3] = 1; a[n_] := a[n] = ((n - 3)*a[n - 3] + (n - 2)*a[n - 2] + (n - 1)*a[n - 1])/n; Flatten[ Position[ Table[a[n], {n, 1, 10^5}], _Integer]]
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CROSSREFS
| Sequence in context: A129315 A171126 A194544 * A135101 A108065 A026336
Adjacent sequences: A075767 A075768 A075769 * A075771 A075772 A075773
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Oct 09 2002
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EXTENSIONS
| Edited, corrected and extended by Robert G. Wilson v (rgwv(AT)rgwv.com), Oct 10 2002
a(14) omwards from Lambert Klasen (lambert.klasen(AT)gmx.net), Jul 27 2005
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