OFFSET
1,3
COMMENTS
Let f(n) = A050376(n) be the n-th Fermi-Dirac prime. The FDH number of a strict integer partition (y_1, ..., y_k) is f(y_1) * ... * f(y_k).
EXAMPLE
45 is the FDH number of (6,4), which has LCM 12, so a(45) = 12.
MATHEMATICA
nn=200;
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)]]]]];
FDprimeList=Array[FDfactor, nn, 1, Union]; FDrules=MapIndexed[(#1->#2[[1]])&, FDprimeList];
LCM@@@Table[Reverse[FDfactor[n]/.FDrules], {n, 2, nn}]
CROSSREFS
KEYWORD
nonn
AUTHOR
Gus Wiseman, Sep 28 2018
STATUS
approved