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A077581 Triangle in which row n contains the n smallest numbers starting from 1 and coprime to n. 12
1, 1, 3, 1, 2, 4, 1, 3, 5, 7, 1, 2, 3, 4, 6, 1, 5, 7, 11, 13, 17, 1, 2, 3, 4, 5, 6, 8, 1, 3, 5, 7, 9, 11, 13, 15, 1, 2, 4, 5, 7, 8, 10, 11, 13, 1, 3, 7, 9, 11, 13, 17, 19, 21, 23, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 1, 5, 7, 11, 13, 17, 19, 23, 25, 29, 31, 35, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
A247815 and A247892 give number of primes and nonprimes per row. - Reinhard Zumkeller, Sep 26 2014
LINKS
EXAMPLE
1;
1, 3;
1, 2, 4;
1, 3, 5, 7;
1, 2, 3, 4, 6;
1, 5, 7, 11, 13, 17;
1, 2, 3, 4, 5, 6, 8;
1, 3, 5, 7, 9, ...
MATHEMATICA
row[n_] := Take[Select[Range[n^2], GCD[ #, n]==1&], n]; Join@@row/@Range[13]
PROG
(Haskell)
a077581 n k = a077581_tabl !! (n-1) !! (k-1)
a077581_row n = a077581_tabl !! (n-1)
a077581_tabl = map (\x -> take x [z | z <- [1..], gcd x z == 1]) [1..]
-- Reinhard Zumkeller, Sep 26 2014
CROSSREFS
Cf. A247798 (central terms), A247815, A247892.
Cf. A077664.
Sequence in context: A251621 A016468 A134839 * A130419 A083110 A059016
KEYWORD
nonn,tabl,easy,look
AUTHOR
Amarnath Murthy, Nov 14 2002
EXTENSIONS
More terms from Sascha Kurz, Jan 11 2003
STATUS
approved

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Last modified May 28 01:34 EDT 2024. Contains 372900 sequences. (Running on oeis4.)