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This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A316265 FDH numbers of strict integer partitions with prime parts.

Original entry on oeis.org

1, 3, 4, 7, 11, 12, 19, 21, 25, 28, 33, 41, 44, 47, 57, 61, 75, 76, 77, 83, 84, 97, 100, 121, 123, 132, 133, 139, 141, 151, 164, 169, 175, 183, 188, 197, 209, 228, 231, 233, 241, 244, 249, 271, 275, 287, 289, 291, 300, 307, 308, 329, 332, 347, 361, 363, 388
Offset: 1

Views

Author

Gus Wiseman, Jun 28 2018

Keywords

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).

Examples

			Sequence of strict integer partitions with prime parts, preceded by their FDH numbers, begins:
   1: ()
   3: (2)
   4: (3)
   7: (5)
  11: (7)
  12: (3,2)
  19: (11)
  21: (5,2)
  25: (13)
  28: (5,3)
  33: (7,2)
  41: (17)
  44: (7,3)
  47: (19)
  57: (11,2)
  61: (23)
  75: (13,2)
  76: (11,3)
  77: (7,5)
  83: (29)
  84: (5,3,2)
		

Crossrefs

Programs

  • Mathematica
    nn=100;
    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];
    Select[Range[nn],And@@PrimeQ/@(FDfactor[#]/.FDrules)&]