OFFSET
1,3
COMMENTS
Conjecture a(n) = 0 only for n = 1, 2 and 4.
EXAMPLE
The partitions of 9 are 9, (8, 1), (7, 2), (6, 3), ...(6, 2, 1), (5, 3, 1), (4, 3, 2) etc. (432 is the largest number obtained as a concatenation of 4, 3, 2).
MAPLE
catL := proc(L) local a, i ; a := op(-1, L) ; for i from 2 to nops(L) do a := a*10^(max(1, ilog10(op(-i, L))+1))+op(-i, L) ; od: RETURN(a) ; end:
A110454 := proc(n) local a, p, m, j ; a := 0 ; for p in combinat[partition](n) do if nops(p) = nops( convert(p, set)) then for j in combinat[permute](p) do m := catL(j) ; if ( m > 4 and not isprime(m) ) and ( m > a) then a := m ; fi ; od: fi ; od: RETURN(a) ; end: # R. J. Mathar, Feb 08 2008
CROSSREFS
KEYWORD
base,nonn
AUTHOR
Amarnath Murthy, Aug 04 2005
EXTENSIONS
a(9) corrected by James A. Sellers, Nov 18 2005
Corrected and extended by R. J. Mathar, Feb 08 2008
STATUS
approved