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A053018 Let Do(n)=A006566(n)=n-th dodecahedral number. Consider all integer triples (i,j,k), j >= k>0, with Do(i)=Do(j)+Do(k), ordered by increasing i; sequence gives j values. 3

%I #18 Jul 09 2022 11:09:54

%S 178,150,2012,4840,7773,8904,17403,22363,24699,26200,21916,22250,

%T 37022,39223,61190,62899,102450,123108,223132,269966,374384,591930,

%U 554636,636031,743699,892780,1295888,1468290,1395491,1822152,1859152,1957822

%N Let Do(n)=A006566(n)=n-th dodecahedral number. Consider all integer triples (i,j,k), j >= k>0, with Do(i)=Do(j)+Do(k), ordered by increasing i; sequence gives j values.

%C i values are A053017 and k values are A053019.

%e Do(179) = 25665020 = 25236484 + 428536 = Do(178) + Do(46);

%e Do(184) = 27880600 = 15086400 + 12794200 = Do(150) + Do(142).

%t (* This is just a recomputation of j values, given i values. *)

%t A053017 = Cases[Import["https://oeis.org/A053017/b053017.txt", "Table"], {_, _}][[All, 2]];

%t do[n_] := n*(3*n - 1)*(3*n - 2)/2;

%t triples = Reap[Module[{s, i, j, k, n, ijk}, s[i_] := Solve[j >= k > 0 && do[i] == do[j] + do[k], {j, k}, Integers]; For[n = 1, n <= Length[A053017], n++, i = A053017[[n]]; ijk = {i, j, k} /. s[i] // First; Print[ijk]; Sow[ijk]]]][[2, 1]];

%t A053018 = triples[[All, 2]] (* _Jean-François Alcover_, Feb 17 2015, updated Jul 09 2022 *)

%K nice,nonn

%O 1,1

%A Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Feb 24 2000

%E More terms from _Jon E. Schoenfield_, Aug 13 2007

%E a(27)-a(32) from _Donovan Johnson_, Aug 15 2010

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Last modified March 28 18:04 EDT 2024. Contains 371254 sequences. (Running on oeis4.)