Original entry on oeis.org
0, 4, 115, 2263, 337040438, 50539060640, 7074108084209, 943101044111145, 121246131347141448, 15154916165017175118, 1852191953202054212155, 222256232357242458252559, 26266027276128286229296330
Offset: 1
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003
A080483
Reverse concatenation of next n numbers with a(1) = 0.
Original entry on oeis.org
0, 21, 543, 9876, 1413121110, 201918171615, 27262524232221, 3534333231302928, 444342414039383736, 54535251504948474645, 6564636261605958575655, 777675747372717069686766, 90898887868584838281807978
Offset: 1
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With[{nn=20},FromDigits[Flatten[IntegerDigits[#]]]&/@(Reverse/@ TakeList[ Range[0,(nn(nn+1))/2],Range[nn]])] (* Requires Mathematica version 11 or later *) (* Harvey P. Dale, Jun 10 2019 *)
More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003
Original entry on oeis.org
0, 7, 181, 3292, 471040370, 67306057205, 9087508077407, 1178111077100976, 148114138013127912, 18178417168316158215, 2188212087201986191885, 259225249124239023228922, 30299629289528279427269326
Offset: 1
Next term has 841 digits.
Corrected and extended by Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003
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).
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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 *)
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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.
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