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A156298
Primes where the first digit is greater than the second digit.
1
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
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
KEYWORD
nonn,base
AUTHOR
Parthasarathy Nambi, Feb 07 2009
EXTENSIONS
More terms from Emeric Deutsch, Feb 28 2009
STATUS
approved