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A116056
n and pi(n) are both made of nontrivial runs of identical digits, where pi(n)=A000720(n).
1
33, 8833, 66644, 66777, 117766, 118811, 990000, 1144000, 9997777, 115522333, 116660044, 116661111, 1100088555, 1100088855, 1100111100, 1100111111, 1100111333, 1100112200, 1100112211, 1100112222, 2277334444, 2277334455, 2277334466, 2277334477, 2277335500, 2288811222
OFFSET
1,1
COMMENTS
A run of length 1 is trivial.
Up to 10^18 there are only 5 prime terms: 9997777, 1122991155533399, 44770077777722233, 440009996622997711, 442244499338866333. - Giovanni Resta, Sep 13 2019
LINKS
Giovanni Resta, Table of n, a(n) for n = 1..418 (terms < 10^18)
EXAMPLE
pi(118811) = 11199, pi(9997777) = 664444.
MATHEMATICA
zyQ[n_] := Min[Length /@ Split[IntegerDigits[n]]] > 1; Select[Range[10^7], zyQ[#] && zyQ[PrimePi[#]] &] (* Giovanni Resta, Sep 13 2019 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Giovanni Resta, Feb 13 2006
EXTENSIONS
More terms from Giovanni Resta, Sep 13 2019
STATUS
approved