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A325100 Heinz numbers of strict integer partitions with no binary carries. 6

%I #6 Jul 27 2019 14:57:51

%S 1,2,3,5,6,7,11,13,14,17,19,21,23,26,29,31,33,35,37,38,41,42,43,47,53,

%T 57,58,59,61,67,69,71,73,74,79,83,86,89,95,97,101,103,106,107,109,111,

%U 113,114,122,123,127,131,133,137,139,142,149,151,157,158,159

%N Heinz numbers of strict integer partitions with no binary carries.

%C A binary carry of two positive integers is an overlap of the positions of 1's in their reversed binary expansion.

%C The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1) * ... * prime(y_k), so these are squarefree numbers whose prime indices have no carries. A prime index of n is a number m such that prime(m) divides n. The multiset of prime indices of n is row n of A112798.

%e The sequence of terms together with their prime indices begins:

%e 1: {}

%e 2: {1}

%e 3: {2}

%e 5: {3}

%e 6: {1,2}

%e 7: {4}

%e 11: {5}

%e 13: {6}

%e 14: {1,4}

%e 17: {7}

%e 19: {8}

%e 21: {2,4}

%e 23: {9}

%e 26: {1,6}

%e 29: {10}

%e 31: {11}

%e 33: {2,5}

%e 35: {3,4}

%e 37: {12}

%e 38: {1,8}

%e 41: {13}

%e 42: {1,2,4}

%t binpos[n_]:=Join@@Position[Reverse[IntegerDigits[n,2]],1];

%t stableQ[u_,Q_]:=!Apply[Or,Outer[#1=!=#2&&Q[#1,#2]&,u,u,1],{0,1}];

%t Select[Range[100],SquareFreeQ[#]&&stableQ[PrimePi/@First/@FactorInteger[#],Intersection[binpos[#1],binpos[#2]]!={}&]&]

%Y Cf. A050315, A056239, A080572, A112798, A247935, A267610.

%Y Cf. A325095, A325096, A325097, A325100, A325101, A325103, A325110, A325119.

%K nonn

%O 1,2

%A _Gus Wiseman_, Mar 28 2019

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Last modified September 17 05:28 EDT 2024. Contains 375985 sequences. (Running on oeis4.)