A193380
A192392(n)/n = largest m such that m*n is a concatenation of the numbers n(n-1)/2+1,...,n(n+1)/2.
Original entry on oeis.org
1, 16, 218, 24277, 282624223, 35336530286, 4038946460332, 454417916411629, 50493713793377093, 5554535251494847465, 605967851146914507796, 65648063122810597558064, 7069922221437372952524460, 714212835424956578936007364364293
Offset: 1
A076072
Largest multiple of n that can be formed by using the digits of the next n numbers, or 0 if no such number exists.
Original entry on oeis.org
1, 32, 654, 97180, 4321111115, 987622111110, 87654322222222, 9654333333332120, 987544444443333210, 98765555555444443210, 9876666666665555524130, 988777777777776666543120, 99998888888888877654321100
Offset: 1
-
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]A076072(n)={ my(d=vecsort(Vec(concat(vector(n,i,Str(i+n*(n-1)/2)))),,4)); for( i=1, (#d)!, eval(concat(d))%n || break; d=precperm(d)); eval(concat(d))} \\ M. F. Hasler, Jul 24 2011
A076069
Largest number formed as concatenation of a permutation of the n consecutive numbers 1+n(n-1)/2, ..., n(n+1)/2 (written in decimal).
Original entry on oeis.org
1, 32, 654, 98710, 1514131211, 212019181716, 28272625242322, 3635343332313029, 454443424140393837, 55545352515049484746, 6665646362616059585756, 787776757473727170696867, 91908988878685848382818079, 9998979695949392105104103102101100
Offset: 1
1, then a concatenation of a permutation of 2 and 3, then a concatenation of a permutation of 4, 5 and 6.
Definition modified to obtain a new sequence different from (earlier duplicate)
A080480. M. F. Hasler, Jun 29 2011.
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.
Original entry on oeis.org
0, 12, 543, 9876, 1413121110, 201918171516, 27262524212322, 3534333231302928, 444342414039383736, 54535251494847464550, 6564636261605958575655, 777675747372717069676668, 90898887868584838281798078, 999897969594939291104103101102100
Offset: 1
a(20) = concat(210,209,...,201,199,...,191,200).
-
lmn[n_]:=Max[Select[FromDigits[Flatten[IntegerDigits/@#]]&/@Permutations[n],Divisible[ #,Length[n]]&]]; Join[{0},lmn/@With[{nn=10},TakeList[Range[(nn(nn+1))/2],Range[2,nn]]]] (* The program generates the first 10 terms of the sequence. To generate more, increase the nn constant but the program may take a long time to run. *) (* Harvey P. Dale, Nov 20 2023 *)
-
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() */
Showing 1-4 of 4 results.
Comments