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.
1, 32, 654, 97108, 1413121115, 212019181716, 28272625222324, 3635343331293032, 454443424140393837, 55545352514948474650, 6665646362616059585756, 787776757473727170696768, 91908988878685848382817980, 9998979695949392105104103101100102
Offset: 1
Programs
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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]
A192392(n)={ my( d=vecsort( vector( n,i,Str( i+n*(n-1)/2 )),,4 ), t ); for( i=1,n!, eval(concat(d))%n || break; d=precperm(d)); eval(concat(d))}
Comments