|
Search: id:A154762
|
|
|
| A154762 |
|
Primes such that number of odd and nonprime digits = number of prime digits |
|
+0
1
|
|
| 13, 17, 29, 31, 59, 71, 79, 97, 103, 107, 163, 167, 241, 269, 281, 349, 389, 421, 431, 439, 479, 509, 541, 569, 613, 617, 631, 659, 701, 709, 761, 769, 821, 829, 839, 859, 907, 947, 967, 983, 1063, 1087, 1123, 1153, 1213, 1217, 1229, 1231, 1259, 1279, 1297
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
Odd and nonprime digits = 1 or 9, prime digits = 2, 3, 5 or 7.
|
|
MAPLE
|
digs1or9 := proc(n) local a, c; a := 0 ; for c in convert(n, base, 10) do if c in {1, 9} then a := a+1 ; end if; end do; a; end proc: A109066 := proc(n) local a, d; p := ithprime(n) ; a := 0 ; for d in convert(p, base, 10) do if isprime(d) then a := a+1 ; end if; end do; a; end proc: for n from 1 to 400 do p := ithprime(n) ; if digs1or9(p) = A109066(n) then printf("%d, ", p) ; fi; od: [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 22 2009]
|
|
CROSSREFS
|
Sequence in context: A152427 A092626 A156343 this_sequence A079348 A061381 A048520
Adjacent sequences: A154759 A154760 A154761 this_sequence A154763 A154764 A154765
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Juri-Stepan Gerasimov (2stepan(AT)rambler.ru), Jan 15 2009
|
|
|
Search completed in 0.002 seconds
|
