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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A360553 Numbers > 1 whose unordered prime signature has integer median. 11
 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 46, 47, 49, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64, 65, 66, 67, 69, 70, 71, 73, 74, 77, 78, 79, 81, 82, 83 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS First differs from A067340 in having 60. A number's unordered prime signature (row n of A118914) is the multiset of positive exponents in its prime factorization. The median of a multiset is either the middle part (for odd length), or the average of the two middle parts (for even length). LINKS Table of n, a(n) for n=1..67. EXAMPLE The unordered prime signature of 60 is {1,1,2}, with median 1, so 60 is in the sequence. The unordered prime signature of 1260 is {1,1,2,2}, with median 3/2, so 1260 is not in the sequence. MATHEMATICA Select[Range[2, 100], IntegerQ[Median[Last/@FactorInteger[#]]]&] CROSSREFS For mean instead of median we have A067340, complement A070011. Positions of even terms in A360460. The complement is A360554 (without 1). These partitions are counted by A360687. - For divisors (A063655) we have A139711, complement A139710. - For prime indices (A360005) we have A359908, complement A359912. - For distinct prime indices (A360457) we have A360550, complement A360551. - For distinct prime factors (A360458) we have A360552, complement A100367. - For prime factors (A360459) we have A359913, complement A072978. - For prime multiplicities (A360460) we have A360553, complement A360554. - For 0-prepended differences (A360555) we have A360556, complement A360557. A112798 lists prime indices, length A001222, sum A056239. A124010 lists prime signature. A325347 = partitions w/ integer median, complement A307683, strict A359907. A359893 and A359901 count partitions by median, odd-length A359902. A360454 = numbers whose prime indices and signature have the same median. Cf. A000975, A026424, A078174, A078175, A316413, A326621, A360453. Sequence in context: A255724 A285100 A368007 * A067340 A263837 A283550 Adjacent sequences: A360550 A360551 A360552 * A360554 A360555 A360556 KEYWORD nonn AUTHOR Gus Wiseman, Feb 16 2023 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 July 21 14:09 EDT 2024. Contains 374474 sequences. (Running on oeis4.)