A352091 Starts of runs of 3 consecutive tribonacci-Niven numbers (A352089).
6, 12, 26, 80, 184, 506, 664, 1602, 1603, 1704, 3409, 6034, 9830, 15723, 16744, 19088, 21230, 21664, 22834, 33544, 39424, 40662, 40730, 51190, 55744, 56224, 60710, 61264, 63734, 66014, 66055, 67144, 67248, 73024, 78064, 81150, 84790, 94086, 95094, 109087, 111880
Offset: 1
Examples
6 is a term since 6, 7 and 8 are all tribonacci-Niven numbers: the minimal tribonacci representation of 6, A278038(6) = 110, has 2 1's and 6 is divisible by 2, the minimal tribonacci representation of 7, A278038(7) = 1000, has one 1 and 7 is divisible by 1, and the minimal tribonacci representation of 8, A278038(8) = 1001, has 2 1's and 8 is divisible by 2.
Links
- Amiram Eldar, Table of n, a(n) for n = 1..10000
Crossrefs
Programs
-
Mathematica
t[1] = 1; t[2] = 2; t[3] = 4; t[n_] := t[n] = t[n - 1] + t[n - 2] + t[n - 3]; triboNivenQ[n_] := Module[{s = {}, m = n, k}, While[m > 0, k = 1; While[t[k] <= m, k++]; k--; AppendTo[s, k]; m -= t[k]; k = 1]; Divisible[n, DigitCount[Total[2^(s - 1)], 2, 1]]]; seq[count_, nConsec_] := Module[{tri = triboNivenQ /@ Range[nConsec], s = {}, c = 0, k = nConsec + 1}, While[c < count, If[And @@ tri, c++; AppendTo[s, k - nConsec]]; tri = Join[Rest[tri], {triboNivenQ[k]}]; k++]; s]; seq[30, 3]