2,1

R. J. Mathar's program confirms a(2) - a(10) and proves that a(11) does not exist.

a(10) = 987654103 = A007810(9). For n >= 3, a(n) < A062813(n), a multiple of n.

a(9) = 42373937 as the prime 42373937 (base 10) = 87654102 (base 9), the largest prime number with distinct digits when represented in base 9.

rebase := proc(L, b) add(op(-i, L)*b^(i-1), i=1..nops(L)) ; end: A132129rec := proc(L, n, ndigs) local a, d ; if nops(L) < ndigs then for d from n-1 to 0 by -1 do if not d in L then a := A132129rec([op(L), d], n, ndigs) ; if a > 0 then RETURN(a) ; fi ; fi ; od: RETURN(-1) ; else a := rebase(L, n) ; if isprime(a) then RETURN(a) ; else RETURN(-1) ; fi ; fi ; end: A132129 := proc(n) local d, L, a, ndgs ; for ndgs from n to 1 by -1 do for d from n-1 to 0 by -1 do L := [d] ; a := A132129rec(L, n, ndgs) ; if a > 0 then RETURN(a) ; fi ; od: od; end: for n from 2 do print(n, A132129(n)) ; od: - R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Oct 24 2007

Cf. A062813, A007810, A029743.

Adjacent sequences: A132126 A132127 A132128 this_sequence A132130 A132131 A132132

Sequence in context: A096481 A065643 A038031 this_sequence A125611 A022119 A042247

base,fini,full,nonn

Rick L. Shepherd (rshepherd2(AT)hotmail.com), Aug 11 2007