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!)
 A327641 Number of partitions of n into divisors d of n such that n/d is squarefree. 0
 1, 1, 2, 2, 2, 2, 8, 2, 2, 2, 11, 2, 8, 2, 14, 14, 2, 2, 8, 2, 11, 18, 20, 2, 8, 2, 23, 2, 14, 2, 742, 2, 2, 26, 29, 26, 8, 2, 32, 30, 11, 2, 1654, 2, 20, 14, 38, 2, 8, 2, 11, 38, 23, 2, 8, 38, 14, 42, 47, 2, 742, 2, 50, 18, 2, 44, 5257, 2, 29, 50, 5066, 2, 8, 2, 59, 14 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,3 LINKS FORMULA a(n) = [x^n] Product_{d|n} 1 / (1 - mu(n/d)^2 * x^d). MATHEMATICA a[n_] := SeriesCoefficient[Product[1/(1 - MoebiusMu[n/d]^2 x^d), {d, Divisors[n]}], {x, 0, n}]; Table[a[n], {n, 0, 75}] PROG (MAGMA) [1] cat [#RestrictedPartitions(n, {d:d in Divisors(n)|IsSquarefree(n div d)}):n in [1..75]]; // Marius A. Burtea, Sep 20 2019 CROSSREFS Cf. A008683, A018818, A225244, A225245, A246655 (positions of 2's). Sequence in context: A054083 A270379 A295557 * A066874 A087577 A323741 Adjacent sequences:  A327638 A327639 A327640 * A327642 A327643 A327644 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Sep 20 2019 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 February 23 06:13 EST 2020. Contains 332159 sequences. (Running on oeis4.)