A113898 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.

1196, 11373, 22517, 33597, 44639, 55646, 60062, 61159, 62256, 63346, 63347, 64448, 64544, 64555, 64577, 64588, 64599, 64611, 64655, 64668, 64700, 64711, 64722, 64774, 64884, 64992, 65545, 65770, 65880, 65881, 65990, 66644, 67746, 68841

Offset: 1

Author

Giovanni Resta, Jan 29 2006

Keywords

• base
• nonn

Comments

Largest value below 10^7 is given by pi(110486) = 10486.

Examples

			pi(64668) = 6468, pi(99551) = 9551.
		

Crossrefs

Cf. A000720, A114924, A080794.

Programs

Mathematica

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