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A117975 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. 1
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; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..111.

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].

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 *)

CROSSREFS

Cf. A117974.

Sequence in context: A177994 A179285 A026835 * A143258 A027199 A140218

Adjacent sequences:  A117972 A117973 A117974 * A117976 A117977 A117978

KEYWORD

nonn,tabl

AUTHOR

Leroy Quet, Apr 06 2006

EXTENSIONS

More terms from Sean A. Irvine, Mar 27 2011

STATUS

approved

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Last modified March 20 20:14 EDT 2019. Contains 321352 sequences. (Running on oeis4.)