OFFSET
1,1
COMMENTS
The greater member of a twin prime pair such that the count of its prime digits is equal to the count of odd digits in the smaller member. - R. J. Mathar, May 19 2010
LINKS
Harvey P. Dale, Table of n, a(n) for n = 1..1000
EXAMPLE
29 and 31 are twin primes; 29 has one odd digit (9) and 31 has one prime digit (3), so 31 is a term.
41 and 43 are twin primes; 41 has one odd digit (1) and 43 has one prime digit (3), so 43 is a term.
71 and 73 are twin primes; 71 has two odd digits (7 and 1) and 73 has two prime digits (7 and 3), so 73 is a term.
MATHEMATICA
Select[Partition[Prime[Range[1000]], 2, 1], #[[2]]-#[[1]]==2&&Count[IntegerDigits[ #[[1]]], _?OddQ]==Count[IntegerDigits[#[[2]]], _?PrimeQ]&][[All, 2]] (* Harvey P. Dale, Aug 08 2022 *)
CROSSREFS
KEYWORD
nonn,base,less
AUTHOR
Juri-Stepan Gerasimov, Mar 16 2009
EXTENSIONS
Corrected (2131 inserted, 2533 replaced by 2593, 2659 inserted, 4231 removed etc.) by R. J. Mathar, May 19 2010
Edited by Jon E. Schoenfield, Apr 18 2021
STATUS
approved