The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A339243 Number of partitions of n into divisors of n where every part appears at least 2 times. 0
 0, 1, 1, 2, 1, 4, 1, 5, 3, 6, 1, 15, 1, 8, 7, 16, 1, 29, 1, 32, 9, 12, 1, 104, 5, 14, 13, 60, 1, 171, 1, 81, 15, 18, 14, 448, 1, 20, 17, 326, 1, 426, 1, 147, 99, 24, 1, 1675, 7, 173, 23, 205, 1, 902, 23, 809, 25, 30, 1, 8616, 1, 32, 183, 682, 27, 1629, 1, 354, 31, 1309 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,4 LINKS Table of n, a(n) for n=1..70. Index entries for sequences related to partitions FORMULA a(n) = [x^n] Product_{d|n} (1 + x^(2*d) / (1 - x^d)). EXAMPLE a(15) = 7 because we have [5, 5, 5], [3, 3, 3, 3, 3], [5, 5, 1, 1, 1, 1, 1], [3, 3, 3, 3, 1, 1, 1], [3, 3, 3, 1, 1, 1, 1, 1, 1], [3, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1] and [1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1]. MATHEMATICA Table[SeriesCoefficient[Product[1 + x^(2 d)/(1 - x^d), {d, Divisors[n]}], {x, 0, n}], {n, 1, 70}] CROSSREFS Cf. A000040 (positions of 1's), A007690, A018818, A027750. Sequence in context: A322100 A277100 A337363 * A214579 A083711 A339619 Adjacent sequences: A339240 A339241 A339242 * A339244 A339245 A339246 KEYWORD nonn AUTHOR Ilya Gutkovskiy, Nov 28 2020 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.

Last modified October 4 15:21 EDT 2023. Contains 365885 sequences. (Running on oeis4.)