OFFSET
1,1
COMMENTS
Indices n such that the smallest digit in prime(n), A060420(n), appears twice in the decimal representation of prime(n). [R. J. Mathar, Jan 12 2009]
LINKS
Robert Israel, Table of n, a(n) for n = 1..10000
EXAMPLE
If 191=prime(n=43), 1=1 and 1<9, the 43=a(6);
If 199=prime(n=45), then 9=9 and 9>1;
If 211=prime(n=47), 1=1 and 1<2, then 47=a(7);
If 223=prime(n=48), 2=2 and 2<3, then 48=a(48), etc.
MAPLE
A060420 := proc(n) convert(ithprime(n), base, 10) ; min(op(%)) ; end: dcount := proc(di, n) local a, d; a := 0 ; convert(n, base, 10) ; for d in % do if d = di then a := a+1 ; fi; od; a ; end: isA154522 := proc(n) local d, c ; d := A060420(n) ; c := dcount(d, ithprime(n)) ; RETURN( c = 2 ) ; end: for n from 1 to 800 do if isA154522(n) then printf("%d, ", n) ; fi; od: # R. J. Mathar, Jan 12 2009
MATHEMATICA
Select[Range[300], Length[Split[Sort[IntegerDigits[Prime[#]]]][[1]]] == 2&] (* Harvey P. Dale, Aug 16 2011 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Juri-Stepan Gerasimov, Jan 11 2009
EXTENSIONS
Removed 205, 206, 208. Added 210. R. J. Mathar, Jan 12 2009
STATUS
approved