A156298 Primes where the first digit is greater than the second digit.

31, 41, 43, 53, 61, 71, 73, 83, 97, 101, 103, 107, 109, 211, 307, 311, 313, 317, 401, 409, 419, 421, 431, 433, 439, 503, 509, 521, 523, 541, 547, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 809

Offset

1,1

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Chris Caldwell, "The first 1000 Primes"

Example

439 is a prime in which the first digit is greater than the second digit.

Maple

a := proc (n) local nn: nn := convert(ithprime(n), base, 10): if nn[nops(nn)-1] < nn[nops(nn)] then ithprime(n) else end if end proc: seq(a(n), n = 5 .. 145); # Emeric Deutsch, Feb 28 2009

Mathematica

Select[Prime[Range[5, 200]], IntegerDigits[#][[1]]>IntegerDigits[#][[2]]&] (* Harvey P. Dale, Jul 25 2021 *)

Crossrefs

Cf. A000040.

Sequence in context: A043981 A146333 A109645 * A099180 A156299 A342216

Adjacent sequences: A156295 A156296 A156297 * A156299 A156300 A156301

Keyword

nonn,base

Author

Parthasarathy Nambi, Feb 07 2009

Extensions

More terms from Emeric Deutsch, Feb 28 2009

Status

approved