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 A193381 Largest multiple of n which is a concatenation of the n numbers n(n-1)/2,...,n(n+1)/2-1, or 0 if no such number exists. 0
 0, 12, 543, 9876, 1413121110, 201918171516, 27262524212322, 3534333231302928, 444342414039383736, 54535251494847464550, 6564636261605958575655, 777675747372717069676668, 90898887868584838281798078, 999897969594939291104103101102100 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS This is to A192392 what is A080481 to A053067: The integers are considered in groups of n=1,2,3,... numbers, starting with {0}, {1,2}, {3,4,5}, ... The sequence lists the concatenation of the permutation of the n elements of each group which yields the largest multiple of n, when written in decimal. LINKS EXAMPLE a(20) = concat(210,209,...,201,199,...,191,200). PROG (PARI) a(n)={my(d=vecsort(vector(n, i, Str(n*(n-1)/2-1+i)), , 4), t); for(i=1, n!, eval(concat(d))%n || return(eval(concat(d))); d=precperm(d))} /* see A076072 for precperm() */ CROSSREFS Sequence in context: A184423 A064344 A163046 * A224539 A210816 A133415 Adjacent sequences:  A193378 A193379 A193380 * A193382 A193383 A193384 KEYWORD nonn,base AUTHOR M. F. Hasler, Jul 24 2011 STATUS approved

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Last modified May 25 12:30 EDT 2019. Contains 323568 sequences. (Running on oeis4.)