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A325994 Heinz numbers of integer partitions such that not every ordered pair of distinct parts has a different quotient. 13

%I #5 Jun 02 2019 23:41:20

%S 42,84,126,168,210,230,252,294,336,378,390,399,420,460,462,504,546,

%T 588,630,672,690,714,742,756,780,798,840,882,920,924,966,1008,1050,

%U 1092,1134,1150,1170,1176,1197,1218,1260,1302,1344,1365,1380,1386,1428,1470,1484

%N Heinz numbers of integer partitions such that not every ordered pair of distinct parts has a different quotient.

%C The Heinz number of an integer partition (y_1,...,y_k) is prime(y_1)*...*prime(y_k).

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

%e 42: {1,2,4}

%e 84: {1,1,2,4}

%e 126: {1,2,2,4}

%e 168: {1,1,1,2,4}

%e 210: {1,2,3,4}

%e 230: {1,3,9}

%e 252: {1,1,2,2,4}

%e 294: {1,2,4,4}

%e 336: {1,1,1,1,2,4}

%e 378: {1,2,2,2,4}

%e 390: {1,2,3,6}

%e 399: {2,4,8}

%e 420: {1,1,2,3,4}

%e 460: {1,1,3,9}

%e 462: {1,2,4,5}

%e 504: {1,1,1,2,2,4}

%e 546: {1,2,4,6}

%e 588: {1,1,2,4,4}

%e 630: {1,2,2,3,4}

%e 672: {1,1,1,1,1,2,4}

%t Select[Range[1000],!UnsameQ@@Divide@@@Subsets[PrimePi/@First/@FactorInteger[#],{2}]&]

%Y The subset case is A325860.

%Y The maximal case is A325861.

%Y The integer partition case is A325853.

%Y The strict integer partition case is A325854.

%Y Heinz numbers of the counterexamples are given by A325994.

%Y Cf. A002033, A056239, A103300, A108917, A112798, A143823, A196724, A325768, A325856, A325868, A325869, A325876.

%K nonn

%O 1,1

%A _Gus Wiseman_, Jun 02 2019

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Last modified April 16 01:40 EDT 2024. Contains 371696 sequences. (Running on oeis4.)