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Search: id:A105327
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| A105327 |
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Numbers n such that pi(n)=pi(d_1!)+pi(d_2!)+...+pi(d_k!) where d_1 d_2 ...d_k is the decimal expansion of n. |
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+0
2
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| 0, 1, 2, 115, 1626, 5370, 5371, 5570, 5571, 6170, 6171, 40854, 373369, 373469, 419386, 419658, 419685, 889609, 889619
(list; graph; listen)
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OFFSET
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1,3
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COMMENT
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There is no further term (the proof is easy).
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LINKS
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Eric Weisstein's World of Mathematics, Link to a section of The World of Mathematics.
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EXAMPLE
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889619 is in the sequence because pi(889619)=pi(8!)+pi(8!)+pi(9!)+pi(6!)+pi(1!)+pi(9!).
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MATHEMATICA
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Do[h = IntegerDigits[m]; l = Length[h]; If[PrimePi[m] == Sum[PrimePi[h[[k]]! ], {k, l}], Print[m]], {m, 0, 3000000}]
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CROSSREFS
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Cf. A066457, A105328.
Adjacent sequences: A105324 A105325 A105326 this_sequence A105328 A105329 A105330
Sequence in context: A140986 A008271 A065670 this_sequence A042681 A024243 A147774
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KEYWORD
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base,fini,full,nonn
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AUTHOR
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Farideh Firoozbakht (f.firoozbakht(AT)math.ui.ac.ir), Apr 20 2005
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