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A117975
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Triangle where a(1,1)=1; a(n,m) = number of positive integers which are missing from row (n-1) of the triangle, are <= n and are coprime to m.
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1
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1, 1, 0, 2, 1, 1, 2, 1, 1, 1, 3, 2, 2, 2, 2, 4, 2, 3, 2, 3, 2, 4, 3, 3, 3, 3, 3, 3, 6, 3, 5, 3, 5, 3, 5, 3, 6, 3, 5, 3, 6, 2, 5, 3, 5, 6, 3, 5, 3, 5, 2, 5, 3, 5, 3, 7, 4, 6, 4, 6, 3, 6, 4, 6, 4, 6, 8, 4, 6, 4, 6, 3, 8, 4, 6, 3, 7, 3, 8, 5, 6, 5, 6, 4, 8, 5, 6, 4, 7, 4, 7, 9, 5, 6, 5, 8, 3, 8, 5, 6, 5, 8, 3, 8, 5, 10, 5, 8, 5, 8, 4
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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EXAMPLE
| Row 5 of the triangle is [3,2,2,2,2]. There are 4 positive integers (1,4,5,6) which are coprime to 1, are <= 6 and are not among the terms of row 5. There are 2 positive integers (1,5) which are <= 6, are coprime to 2 and are not among the terms of row 5. ...(Skipping over the m = 3, 4 and 5 cases.) There are 2 positive integer (1,5) which are <= 6, are coprime to 6 and do not occur in row 5.
So row 6 is [4,2,3,2,3,2].
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MATHEMATICA
| prev = {1}; Flatten[Join[{prev}, Table[prev = Table[Length[Select[Complement[Range[n], prev], CoprimeQ[#, m] &]], {m, n}], {n, 2, 14}]]] (* T. D. Noe, Mar 30 2011 *)
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CROSSREFS
| Cf. A117974.
Sequence in context: A177994 A179285 A026835 * A143258 A027199 A140218
Adjacent sequences: A117972 A117973 A117974 * A117976 A117977 A117978
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KEYWORD
| nonn,tabl
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AUTHOR
| Leroy Quet, Apr 06 2006
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EXTENSIONS
| More terms from Sean A. Irvine (sairvin(AT)xtra.co.nz), Mar 27 2011
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