A157138 Even numbers k such that k and prime(k) have the same number of even digits.

10, 14, 18, 38, 48, 52, 54, 58, 60, 70, 76, 80, 82, 86, 92, 94, 96, 98, 112, 114, 124, 132, 136, 138, 140, 142, 144, 158, 170, 174, 180, 192, 194, 198, 234, 236, 252, 254, 258, 290, 306, 318, 320, 324, 326, 342, 348, 350, 352, 356, 364, 366, 368, 370, 374, 376

Offset

1,1

Comments

Can this sequence be proved to be infinite?

Links

Table of n, a(n) for n=1..56.

Example

10 is a term: prime(10)=29, and 10 and 29 each have 1 even digit.
14 is a term: prime(14)=43, and 14 and 43 each have 1 even digit.
18 is a term: prime(18)=61, and 18 and 61 each have 1 even digit.
124 is a term: prime(124)=683, and 124 and 683 each have 2 even digits.

Crossrefs

Cf. A000027, A000040, A155548, A196563.

Sequence in context: A250197 A055985 A190888 * A131693 A255532 A307516

Adjacent sequences: A157135 A157136 A157137 * A157139 A157140 A157141

Keyword

nonn,base,less

Author

Juri-Stepan Gerasimov, Feb 24 2009

Extensions

Roughly 50 percent of the entries corrected by R. J. Mathar, Feb 26 2009

Edited by Jon E. Schoenfield, Apr 18 2021

Status

approved