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 A327905 FDH numbers of pairwise coprime sets. 0
 2, 6, 8, 10, 12, 14, 18, 20, 21, 22, 24, 26, 28, 32, 33, 34, 35, 38, 40, 42, 44, 46, 48, 50, 52, 55, 56, 57, 58, 62, 63, 66, 68, 70, 74, 75, 76, 77, 80, 82, 84, 86, 88, 91, 93, 94, 95, 96, 98, 99, 100, 104, 106, 110, 112, 114, 116, 118, 122, 123, 125, 126, 132 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Let f(n) = A050376(n) be the n-th Fermi-Dirac prime. The FDH-number of a strict partition or finite set {y_1,...,y_k} is f(y_1)*...*f(y_k). We use the Mathematica function CoprimeQ, meaning a singleton is not coprime unless it is {1}. LINKS Wolfram Language Documentation, CoprimeQ EXAMPLE The sequence of terms together with their corresponding coprime sets begins:    2: {1}    6: {1,2}    8: {1,3}   10: {1,4}   12: {2,3}   14: {1,5}   18: {1,6}   20: {3,4}   21: {2,5}   22: {1,7}   24: {1,2,3}   26: {1,8}   28: {3,5}   32: {1,9}   33: {2,7}   34: {1,10}   35: {4,5}   38: {1,11}   40: {1,3,4}   42: {1,2,5} MATHEMATICA FDfactor[n_]:=If[n==1, {}, Sort[Join@@Cases[FactorInteger[n], {p_, k_}:>Power[p, Cases[Position[IntegerDigits[k, 2]//Reverse, 1], {m_}->2^(m-1)]]]]]; nn=100; FDprimeList=Array[FDfactor, nn, 1, Union]; FDrules=MapIndexed[(#1->#2[[1]])&, FDprimeList]; Select[Range[nn], CoprimeQ@@(FDfactor[#]/.FDrules)&] CROSSREFS Heinz numbers of pairwise coprime partitions are A302696 (all), A302797 (strict), A302569 (with singletons), and A302798 (strict with singletons). FDH numbers of relatively prime sets are A319827. Cf. A050376, A056239, A064547, A213925, A259936, A299755, A299757, A304711, A319826, A326675. Sequence in context: A173634 A005795 A319827 * A157502 A216032 A076300 Adjacent sequences:  A327902 A327903 A327904 * A327906 A327907 A327908 KEYWORD nonn AUTHOR Gus Wiseman, Sep 30 2019 STATUS approved

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Last modified September 18 01:39 EDT 2021. Contains 347504 sequences. (Running on oeis4.)