A074815 Numbers k such that there are no prime numbers between reverse(k) and 3*k.

0, 14, 247, 298, 1003, 2998, 10003, 12473, 17525, 19995, 27528, 29998, 199995, 299998, 1000003, 1824745, 1875265, 1999995, 2124736, 2475247, 2700018, 3124739, 10000003, 12999983, 19999995, 29999998, 30000009, 124752473, 140000024, 170000015, 175247525

Offset

1,2

Comments

Numbers k such that the number of primes between k and 3k (inclusive) = number of primes between k and reverse(k) (inclusive).

Links

Table of n, a(n) for n=1..31.

Example

14 is a term since there are 7 primes between 14 and 41 and 7 primes between 14 and 3*14 = 42.

Crossrefs

Sequence in context: A326651 A055477 A123774 * A280122 A051622 A113377

Adjacent sequences: A074812 A074813 A074814 * A074816 A074817 A074818

Keyword

base,nonn

Author

Jason Earls, Sep 08 2002

Extensions

More terms from Lior Manor Sep 17 2002

Offset corrected and more terms from Sean A. Irvine, Jan 29 2025

Status

approved