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A107120
Numbers n such that pi(n)=prime(d_1*d_2*...*d_k) where d_1 d_2 ... d_k is the decimal expansion of n.
2
162, 242, 291, 371, 461, 515, 2419, 2815, 11874, 64751, 81927, 264961, 276184, 757155, 2537825, 7717729, 9548491, 14738827, 19728438, 19728446, 19728464, 23695527, 77362954, 269776516, 269776523, 269776532, 358399327, 2385883646, 59955748691, 67893872935, 848472784869
OFFSET
1,1
COMMENTS
A107121 is a subsequence of this sequence (see the comments line of A107121). There is no further term up to 52000000.
a(32) > 7*10^14, if it exists. - Giovanni Resta, Jun 01 2020
EXAMPLE
23695527 is in the sequence because pi(23695527)=prime(2*3*6*9*5*5*2*7).
MATHEMATICA
Do[h = IntegerDigits[m]; l = Length[h]; If[Min[h] > 0 && PrimePi[m] == Prime[Product[h[[k]], {k, l}]], Print[m]], {m, 52000000}]
CROSSREFS
Sequence in context: A045227 A066476 A259220 * A045010 A372972 A373737
KEYWORD
nonn,base
AUTHOR
Farideh Firoozbakht, May 13 2005
EXTENSIONS
a(23)-a(28) from Donovan Johnson, Jul 12 2010
a(29)-a(31) from Giovanni Resta, Jun 01 2020
STATUS
approved