cp's OEIS Frontend

A192392 Largest multiple of n which can be formed as concatenation of the next n numbers, {1+n(n-1)/2,...,n(n+1)/2} (written in decimal), or 0 if no such number exists.

%I A192392 #13 Mar 31 2012 13:48:31
%S A192392 1,32,654,97108,1413121115,212019181716,28272625222324,
%T A192392 3635343331293032,454443424140393837,55545352514948474650,
%U A192392 6665646362616059585756,787776757473727170696768,91908988878685848382817980,9998979695949392105104103101100102
%N A192392 Largest multiple of n which can be formed as concatenation of the next n numbers, {1+n(n-1)/2,...,n(n+1)/2} (written in decimal), or 0 if no such number exists.
%C A192392 Equal to A076069(n) whenever A076069(n) is a multiple of n. Less than or equal to A076072(n), where permutations of individual digits are allowed.
%o A192392 (PARI) precperm(p)={ my(t); forstep( i=#p-1,1,-1, p[i]>p[i+1] && for( j=1,#t=vecsort( vecextract( p, 2^#p-2^(i-1) ),,4), t[j]<p[i] && return( concat([ vecextract( p,2^(i-1)-1 ), [t[j]], vecextract( t, Str( "^"j ))])))); vecsort(p,,4)}
%o A192392 A192392(n)={ my( d=vecsort( vector( n,i,Str( i+n*(n-1)/2 )),,4 ), t );
%o A192392  for( i=1,n!, eval(concat(d))%n || break; d=precperm(d)); eval(concat(d))}
%Y A192392 Cf. A076068, A076069, A076072, A080479, A080480.
%K A192392 nonn,base
%O A192392 1,2
%A A192392 _M. F. Hasler_, Jun 29 2011