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 A143239 Triangle read by rows, A126988 * A128407 as infinite lower triangular matrices. 2
 1, 2, -1, 3, 0, -1, 4, -2, 0, 0, 5, 0, 0, 0, -1, 6, -3, -2, 0, 0, 1, 7, 0, 0, 0, 0, 0, -1, 8, -4, 0, 0, 0, 0, 0, 0, 9, 0, -3, 0, 0, 0, 0, 0, 0, 10, -5, 0, 0, -2, 0, 0, 0, 0, 1, 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 12, -6, -4, 0, 0, 2, 0, 0, 0, 0, 0, 0, 13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1, 14, -7, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 1 (list; table; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Row sums = A000010, phi(n): (1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10, 4,...); as a consequence of the Dedekind-Liouville rule illustrated in the example and on p. 137 of "Concrete Mathematics". REFERENCES Ronald L. Graham, Donald E. Knuth & Oren Patashnik, "Concrete Mathematics" 2nd ed.; Addison-Wesley, 1994, p. 137. LINKS FORMULA Triangle read by rows generated from the Dedekind-Liouville rule: T(n,k) = mu(k)*(n/k) if k divides n. T(n,k) = 0 if k is not a divisor of n. Equals A126988 * A128407 EXAMPLE First few rows of the triangle are: 1; 2, -1; 3, 0, -1; 4, -2, 0, 0; 5, 0, 0, 0, -1; 6, -3, -2, 0, 0, 1; 7, 0, 0, 0, 0, 0, -1; 8, -4, 0, 0, 0, 0, 0, 0; 9, 0, -3, 0, 0, 0, 0, 0, 0; 10, -5, 0, 0, -2, 0, 0, 0, 0, 1; 11, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1; 12, -6, -4, 0, 0, 2, 0, 0, 0, 0, 0, 0; 13, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, -1; 14, -7, 0, 0, 0, 0, -2, 0, 0, 0, 0, 0, 0, 1; ... Row 12 = (12, -6, -4, 0, 0, 2, 0, 0, 0, 0, 0, 0) since (Cf. A126988 - the divisors of 12 are (12, 6, 4, 3, 0, 2, 0, 0, 0, 0, 0, 1) and applying mu(k) * (nonzero terms), we get (1*12, (-1)*6, (-1)*4, 1*2) sum = 4 = phi(12). CROSSREFS Cf. A000010, A128407, A126988, A008683. Sequence in context: A127094 A221642 A158906 * A158951 A126988 A280499 Adjacent sequences:  A143236 A143237 A143238 * A143240 A143241 A143242 KEYWORD tabl,sign AUTHOR Gary W. Adamson, Aug 01 2008 STATUS approved

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Last modified October 21 11:10 EDT 2018. Contains 316414 sequences. (Running on oeis4.)