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!)
 A304713 Squarefree numbers whose prime indices are pairwise indivisible. Heinz numbers of strict integer partitions with pairwise indivisible parts. 28
 1, 2, 3, 5, 7, 11, 13, 15, 17, 19, 23, 29, 31, 33, 35, 37, 41, 43, 47, 51, 53, 55, 59, 61, 67, 69, 71, 73, 77, 79, 83, 85, 89, 91, 93, 95, 97, 101, 103, 107, 109, 113, 119, 123, 127, 131, 137, 139, 141, 143, 145, 149, 151, 155, 157, 161, 163, 165, 167, 173 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS A prime index of n is a number m such that prime(m) divides n. The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). LINKS EXAMPLE Sequence of entries together with their corresponding multiset multisystems (see A302242) begins: 1:  {} 2:  {{}} 3:  {{1}} 5:  {{2}} 7:  {{1,1}} 11: {{3}} 13: {{1,2}} 15: {{1},{2}} 17: {{4}} 19: {{1,1,1}} 23: {{2,2}} 29: {{1,3}} 31: {{5}} 33: {{1},{3}} 35: {{2},{1,1}} MATHEMATICA Select[Range[300], SquareFreeQ[#]&&Select[Tuples[PrimePi/@First/@FactorInteger[#], 2], UnsameQ@@#&&Divisible@@#&]==={}&] CROSSREFS Cf. A000009, A005117, A006126, A056239, A073576, A285572, A285573, A293606, A293993, A302696, A302796, A303362, A303365, A304711. Sequence in context: A102553 A069161 A328603 * A319327 A319319 A003277 Adjacent sequences:  A304710 A304711 A304712 * A304714 A304715 A304716 KEYWORD nonn AUTHOR Gus Wiseman, May 17 2018 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 March 30 19:43 EDT 2020. Contains 333127 sequences. (Running on oeis4.)