The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A023033 Number of compositions of n into 8 ordered relatively prime parts. 8
 1, 8, 36, 120, 330, 792, 1716, 3432, 6434, 11440, 19440, 31824, 50352, 77520, 116160, 170544, 244826, 346104, 479908, 657792, 886314, 1184040, 1557312, 2035800, 2623140, 3365736, 4260608, 5379616, 6704742, 8347680, 10263648, 12619464 (list; graph; refs; listen; history; text; internal format)
 OFFSET 8,2 LINKS Marius A. Burtea, Table of n, a(n) for n = 8..5000 N. J. A. Sloane, Transforms FORMULA Moebius transform of C(n-1,7). G.f.: Sum_{k>=1} mu(k) * x^(8*k) / (1 - x^k)^8. - Ilya Gutkovskiy, Feb 05 2020 MAPLE with(numtheory): a:= n-> add(mobius(n/d)*binomial(d-1, 7), d=divisors(n)): seq(a(n), n=8..50);  # Alois P. Heinz, Feb 05 2020 MATHEMATICA a[n_]:=DivisorSum[n, Binomial[# - 1, 7] MoebiusMu[n/#]&]; Array[a, 37, 8] (* or *) a[n_]:=Sum[Boole[Divisible[n, k]] MoebiusMu[n/k] Binomial[k - 1, 7], {k, 1, n}]; Table[a[n], {n, 8, 45}] (* Vincenzo Librandi, Feb 07 2020 *) PROG (MAGMA) [&+[MoebiusMu(n div d)*Binomial(d-1, 7):d in Divisors(n)]:n in[8..40]]; // Marius A. Burtea, Feb 07 2020 CROSSREFS Cf. A000741, A000742, A000743, A023031, A023032, A023034, A023035. Sequence in context: A008500 A306941 A008490 * A278971 A000580 A290995 Adjacent sequences:  A023030 A023031 A023032 * A023034 A023035 A023036 KEYWORD nonn AUTHOR STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 15 09:42 EDT 2020. Contains 336487 sequences. (Running on oeis4.)