The OEIS mourns the passing of Jim Simons and is grateful to the Simons Foundation for its support of research in many branches of science, including the OEIS.
login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A083290 Number of partitions of n into distinct parts which are coprime to n and which are also pairwise relatively prime. 4
1, 0, 1, 1, 2, 1, 3, 2, 3, 2, 7, 2, 9, 3, 4, 5, 16, 3, 20, 4, 8, 7, 31, 5, 22, 9, 18, 9, 54, 4, 68, 16, 21, 16, 28, 11, 112, 20, 32, 18, 144, 9, 173, 22, 33, 40, 221, 19, 139, 25, 71, 43, 327, 25, 117, 47, 103, 80, 475, 18, 568, 90, 98, 122, 191, 29, 805, 93, 197, 44 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,5
COMMENTS
a(n) <= A036998(n); see A082415 for numbers m with a(m) = A036998(m).
LINKS
EXAMPLE
a(7) = 3 since 7 = 3+4 = 2+5 = 1+6; 7 = 1+2+4 does not count (A036998(7)=4).
MATHEMATICA
a[n_] := a[n] = If[n == 1, 1, Module[{ip}, ip = IntegerPartitions[n, All, Select[Range[n - 1], CoprimeQ[#, n] &]]; Length@Select[ip, Sort[#] == Union[#] && AllTrue[Subsets[#, {2}], CoprimeQ @@ # &] &]]];
Table[Print[n, " ", a[n]]; a[n], {n, 1, 80}] (* Jean-François Alcover, Dec 12 2021 *)
PROG
(PARI) a(n)={local(Cache=Map()); my(recurse(r, p, k)=my(hk=[r, p, k], z); if(!mapisdefined(Cache, hk, &z), z=if(k==0, r==0, self()(r, p, k-1) + if(gcd(p, k)==1, self()(r-k, p*k, min(r-k, k-1)))); mapput(Cache, hk, z)); z); recurse(n, n, n)} \\ Andrew Howroyd, Apr 20 2021
CROSSREFS
Sequence in context: A323273 A100677 A188637 * A121842 A317963 A219609
KEYWORD
nonn
AUTHOR
Reinhard Zumkeller, Apr 23 2003
EXTENSIONS
Terms a(31) and beyond from Andrew Howroyd, Apr 20 2021
STATUS
approved

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

License Agreements, Terms of Use, Privacy Policy. .

Last modified May 21 17:21 EDT 2024. Contains 372738 sequences. (Running on oeis4.)