cp's OEIS Frontend

A302797 Squarefree numbers whose prime indices are pairwise coprime. Heinz numbers of strict integer partitions with pairwise coprime parts.

%I A302797 #5 Apr 13 2018 21:54:46
%S A302797 1,2,6,10,14,15,22,26,30,33,34,35,38,46,51,55,58,62,66,69,70,74,77,82,
%T A302797 85,86,93,94,95,102,106,110,118,119,122,123,134,138,141,142,143,145,
%U A302797 146,154,155,158,161,165,166,170,177,178,186,187,190,194,201,202
%N A302797 Squarefree numbers whose prime indices are pairwise coprime. Heinz numbers of strict integer partitions with pairwise coprime parts.
%C A302797 A prime index of n is a number m such that prime(m) divides n. Two or more numbers are coprime if no pair of them has a common divisor other than 1. A single number is not considered coprime unless it is equal to 1.
%C A302797 The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).
%e A302797 Sequence of terms together with their sets of prime indices begins:
%e A302797 01 : {}
%e A302797 02 : {1}
%e A302797 06 : {1,2}
%e A302797 10 : {1,3}
%e A302797 14 : {1,4}
%e A302797 15 : {2,3}
%e A302797 22 : {1,5}
%e A302797 26 : {1,6}
%e A302797 30 : {1,2,3}
%e A302797 33 : {2,5}
%e A302797 34 : {1,7}
%e A302797 35 : {3,4}
%e A302797 38 : {1,8}
%e A302797 46 : {1,9}
%e A302797 51 : {2,7}
%e A302797 55 : {3,5}
%e A302797 58 : {1,10}
%e A302797 62 : {1,11}
%e A302797 66 : {1,2,5}
%e A302797 69 : {2,9}
%e A302797 70 : {1,3,4}
%t A302797 Select[Range[100],Or[#===1,SquareFreeQ[#]&&CoprimeQ@@PrimePi/@FactorInteger[#][[All,1]]]&]
%Y A302797 Cf. A001222, A003963, A005117, A007359, A051424, A056239, A275024, A289509, A302242, A302505, A302696, A302697, A302698, A302796, A302798.
%K A302797 nonn
%O A302797 1,2
%A A302797 _Gus Wiseman_, Apr 13 2018