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A105327 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. 1
0, 1, 2, 115, 1626, 5370, 5371, 5570, 5571, 6170, 6171, 40854, 373369, 373469, 419386, 419658, 419685, 889609, 889619 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

There is no further term (the proof is easy).

LINKS

Table of n, a(n) for n=1..19.

Eric Weisstein's World of Mathematics, Factorial.

EXAMPLE

889619 is in the sequence because pi(889619)=pi(8!)+pi(8!)+pi(9!)+pi(6!)+pi(1!)+pi(9!).

MATHEMATICA

Do[h = IntegerDigits[m]; l = Length[h]; If[PrimePi[m] == Sum[PrimePi[h[[k]]! ], {k, l}], Print[m]], {m, 0, 3000000}]

CROSSREFS

Cf. A066457, A105328.

Sequence in context: A008271 A209184 A065670 * A260334 A257939 A203607

Adjacent sequences:  A105324 A105325 A105326 * A105328 A105329 A105330

KEYWORD

base,fini,full,nonn

AUTHOR

Farideh Firoozbakht, Apr 20 2005

STATUS

approved

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Last modified September 22 00:42 EDT 2020. Contains 337276 sequences. (Running on oeis4.)