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%I #6 Jul 22 2021 07:52:11
%S 1196,11373,22517,33597,44639,55646,60062,61159,62256,63346,63347,
%T 64448,64544,64555,64577,64588,64599,64611,64655,64668,64700,64711,
%U 64722,64774,64884,64992,65545,65770,65880,65881,65990,66644,67746,68841
%N Numbers k such that the value pi(k), the number of primes <= k, can be obtained deleting some of the repeating adjacent digits of k.
%C Largest value below 10^7 is given by pi(110486) = 10486.
%e pi(64668) = 6468, pi(99551) = 9551.
%t lst = {}; p=0; While[p < 10^7, n=PrimePi[ ++p]; {sp, sn}=Split/@IntegerDigits@{p, n}; If[First/@sp==First/@sn && And@@GreaterEqual@@@Transpose[Length/@#&/@{sp, sn}], AppendTo[lst, p]]]; lst
%Y Cf. A000720, A114924, A080794.
%K base,nonn
%O 1,1
%A _Giovanni Resta_, Jan 29 2006
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