The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A302796 Squarefree numbers whose prime indices are relatively prime. Nonprime Heinz numbers of strict integer partitions with relatively prime parts. 26
 1, 2, 6, 10, 14, 15, 22, 26, 30, 33, 34, 35, 38, 42, 46, 51, 55, 58, 62, 66, 69, 70, 74, 77, 78, 82, 85, 86, 93, 94, 95, 102, 105, 106, 110, 114, 118, 119, 122, 123, 130, 134, 138, 141, 142, 143, 145, 146, 154, 155, 158, 161, 165, 166, 170, 174, 177, 178, 182 (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. Two or more numbers are relatively prime if they have no common divisor other than 1. A single number is not considered relatively prime unless it is equal to 1. The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k). LINKS EXAMPLE Sequence of terms together with their sets of prime indices begins: 01 : {} 02 : {1} 06 : {1,2} 10 : {1,3} 14 : {1,4} 15 : {2,3} 22 : {1,5} 26 : {1,6} 30 : {1,2,3} 33 : {2,5} 34 : {1,7} 35 : {3,4} 38 : {1,8} 42 : {1,2,4} 46 : {1,9} 51 : {2,7} 55 : {3,5} 58 : {1,10} 62 : {1,11} 66 : {1,2,5} MATHEMATICA Select[Range[100], Or[#===1, SquareFreeQ[#]&&GCD@@PrimePi/@FactorInteger[#][[All, 1]]===1]&] PROG (PARI) isok(n) = {if (n == 1, return (1)); if (issquarefree(n), my(f = factor(n)); return (gcd(vector(#f~, k, primepi(f[k, 1]))) == 1); ); } \\ Michel Marcus, Apr 13 2018 CROSSREFS Cf. A001222, A003963, A005117, A007359, A051424, A056239, A275024, A289509, A302242, A302505, A302696, A302697, A302698, A302797, A302798. Sequence in context: A281974 A080324 A165562 * A302797 A130319 A191256 Adjacent sequences:  A302793 A302794 A302795 * A302797 A302798 A302799 KEYWORD nonn AUTHOR Gus Wiseman, Apr 13 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 January 20 19:53 EST 2020. Contains 331096 sequences. (Running on oeis4.)