A098683 - OEIS

A098683

Numbers n such that pi(n) = prime(d_1)*prime(d_2)*...*prime(d_k) where d_1 d_2 ... d_k is the decimal expansion of n.

123, 5224, 11166, 51174, 172451, 546322, 14355351, 23539612, 23539621, 24322837, 122924349, 4575242147, 42256772524, 283186883151, 623286236455, 665318971119, 665318971191, 5257788212426, 27452719198281, 273643846355134, 787812731751347, 787812731751374

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OFFSET

1,1

COMMENTS

a(n) must necessarily be a zeroless number, i.e., the sequence is a subsequence of A052382. - Chai Wah Wu, Mar 04 2019

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

122924349 is in the sequence because pi(122924349) = P(1)*P(2)*P(2)*P(9)*P(2)*P(4)*P(3)*P(4)*P(9) where P(i) is i-th prime.

MATHEMATICA

Do[d=IntegerDigits[n]; k=Length[d]; If[ !MemberQ[d, 0]&&PrimePi[n]==Product[Prime[d[[j]]], {j, k}], Print[n]], {n, 230000000}]

CROSSREFS