OFFSET
1,2
COMMENTS
Numbers n such that concatenation of proper divisors of n exceeds that of all smaller numbers. Empty concatenation is regarded as 0.
Sequence has many terms in common with A034090 (numbers n such that sum of proper divisors of n exceeds that of all smaller numbers), A034287 (numbers n such that product of divisors of n is larger than for any number less than n), A034288 (product of proper divisors is larger than for any smaller number), A067128 (Ramanujan's largely composite numbers, defined to be n such that d(n) >= d(k) for k = 1 to n-1).
LINKS
Klaus Brockhaus, Table of n, a(n) for n=1..144
MATHEMATICA
DeleteDuplicates[Table[{n, If[CompositeQ[n], FromDigits[Flatten[IntegerDigits/@Rest[ Most[ Divisors[n]]]]], 0]}, {n, 30000}], GreaterEqual[#1[[2]], #2[[2]]]&][[;; , 1]] (* Harvey P. Dale, Apr 27 2024 *)
PROG
(PARI) {map(n) = local(d); d=divisors(n); if(#d<3, 0, d[1]=""; eval(concat(vecextract(d, concat("..", #d-1)))))} {m=28000; r=-1; for(n=1, m, if(r<(a=map(n)), r=a; print1(n, ", ")))}
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Klaus Brockhaus, Aug 05 2007
STATUS
approved