cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-5 of 5 results.

A116543 Number of terms in greedy representation of n in terms of the Lucas numbers.

Original entry on oeis.org

0, 1, 1, 1, 1, 2, 2, 1, 2, 2, 2, 1, 2, 2, 2, 2, 3, 3, 1, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 1, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 4, 4, 1, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 4, 4, 2, 3, 3, 3, 3, 4, 4, 3, 4, 4, 4, 1, 2, 2, 2, 2, 3, 3, 2, 3, 3, 3, 2, 3, 3, 3, 3, 4, 4, 2, 3, 3, 3, 3, 4, 4, 3, 4, 4, 4, 2
Offset: 0

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Author

James E Davis, Mar 28 2006, Jun 07 2006

Keywords

Comments

I have been studying A007895 and similar sequences and created this sequence as an analog of A007895 for the Lucas sequence (A000032).

Examples

			a(12)=2 because 12=11+1.
		

Crossrefs

Programs

  • Mathematica
    s = Reverse[Sort[Table[LucasL[n - 1], {n, 1, 22}]]];
    t = Map[Length[Select[Reap[FoldList[(Sow[Quotient[#1, #2]]; Mod[#1, #2]) &, #, s]][[2,1]], # > 0 &]] &, Range[1000]] (* Peter J. C. Moses, Oct 18 2012 *)

Formula

Let L(n) = max(Lucas numbers < n). Then a(0) = 0, a(n) = 1 + a(n-L(n)).
a(n) = A007953(A130310(n)). - Amiram Eldar, Feb 17 2022

Extensions

Edited by N. J. A. Sloane, Aug 10 2007
a(0) added by Amiram Eldar, Feb 17 2022

A351720 Numbers k such that k and k + 1 are both lazy-Lucas-Niven numbers (A351719).

Original entry on oeis.org

1, 175, 216, 399, 656, 729, 737, 759, 1000, 1991, 2716, 2820, 2925, 3970, 4068, 4224, 4499, 4641, 5316, 5819, 6565, 6720, 6902, 7890, 9840, 10751, 11843, 12194, 12614, 13034, 13272, 14909, 15483, 15495, 16029, 17234, 17444, 17731, 18074, 18885, 19305, 19669, 20188
Offset: 1

Views

Author

Amiram Eldar, Feb 17 2022

Keywords

Examples

			175 is a term since 175 and 176 are both lazy-Lucas-Niven numbers: the maximal Lucas representation of 175, A130311(175) = 1110110101, has 7 1's and 175 is divisible by 5, and the maximal Lucas representation of 176, A130311(7) = 1110110111, has 8 1's and 176 is divisible by 8.
		

Crossrefs

Subsequence of A351719.
A351721 is a subsequence.

Programs

  • Mathematica
    lazy = Select[IntegerDigits[Range[10^6], 2], SequenceCount[#, {0, 0}] == 0 &]; t = Total[#*Reverse@LucasL[Range[0, Length[#] - 1]]] & /@ lazy; s = FromDigits /@ lazy[[TakeWhile[Flatten[FirstPosition[t, #] & /@ Range[Max[t]]], NumberQ]]]; SequencePosition[Divisible[Range[Length[s]], Plus @@@ IntegerDigits[s]], {True, True}][[;; , 1]]

A351721 Starts of runs of 3 consecutive lazy-Lucas-Niven numbers (A351719).

Original entry on oeis.org

607068, 640618, 665720, 900921, 1000880, 1375940, 1505878, 1537250, 1924224, 1938508, 1966338, 2527998, 3394224, 3935424, 4242624, 4476624, 4747224, 4794624, 5351367, 5401824, 5526024, 5636356, 5992298, 6103900, 6343298, 7028362, 7113024, 8879424, 8998262, 9431424
Offset: 1

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Author

Amiram Eldar, Feb 17 2022

Keywords

Comments

Conjecture: There are no runs of 4 consecutive lazy-Lucas-Niven numbers (checked up to 3*10^9).

Examples

			607068 is a term since 607068, 607069 and 607070 are all divisible by the number of terms in their maximal representation:
     k                   A130311(k)  A131343(k)  k/A131343(k)
-------------------------------------------------------------
607068  111010101010101011110111101         18          33726
607069  111010101010101011110111111         19          31951
607070  111010101010101011111010110         17          35710
		

Crossrefs

A130311 Maximal (or "lazy") Lucas representation of n. Binary system for representing integers using Lucas numbers (A000032) as a base.

Original entry on oeis.org

0, 10, 1, 11, 110, 101, 111, 1011, 1110, 1101, 1111, 10110, 10101, 10111, 11011, 11110, 11101, 11111, 101011, 101110, 101101, 101111, 110110, 110101, 110111, 111011, 111110, 111101, 111111, 1010110, 1010101, 1010111, 1011011, 1011110, 1011101, 1011111, 1101011, 1101110
Offset: 0

Views

Author

Casey Mongoven, May 21 2007; corrected Mar 23 2008

Keywords

Examples

			a(7) = 1110 because 4 + 3 + 1 = 8.
a(8) = 1101 because 4 + 3 + 2 = 9.
		

References

  • Edouard Zeckendorf, Représentation des nombres naturels par une somme des nombres de Fibonacci ou de nombres de Lucas, Bull. Soc. Roy. Sci. Liège, Vol. 41 (1972), pp. 179-182.

Crossrefs

Programs

  • Mathematica
    lazy = Select[IntegerDigits[Range[10^2], 2], SequenceCount[#, {0, 0}] == 0 &]; t = Total[# * Reverse@LucasL[Range[0, Length[#] - 1]]] & /@ lazy; Join[{0}, FromDigits /@ lazy[[TakeWhile[Flatten[FirstPosition[t, #] & /@ Range[Max[t]]], NumberQ]]]] (* Amiram Eldar, Feb 17 2022 *)

Extensions

a(0) and more terms from Amiram Eldar, Feb 17 2022

A351719 Lazy-Lucas-Niven numbers: numbers divisible by the number of terms in their maximal (or lazy) representation in terms of the Lucas numbers (A130311).

Original entry on oeis.org

1, 2, 4, 6, 9, 12, 16, 20, 25, 40, 42, 54, 60, 66, 78, 84, 91, 96, 104, 112, 120, 126, 144, 154, 161, 168, 175, 176, 180, 182, 184, 192, 203, 210, 216, 217, 224, 232, 234, 240, 243, 264, 270, 280, 288, 304, 306, 310, 315, 320, 322, 328, 336, 344, 350, 360, 378
Offset: 1

Views

Author

Amiram Eldar, Feb 17 2022

Keywords

Comments

Numbers k such that A131343(k) | k.

Examples

			6 is a term since its maximal Lucas representation, A130311(6) = 111, has A131343(6) = 3 1's and 6 is divisible by 3.
		

Crossrefs

Programs

  • Mathematica
    lazy = Select[IntegerDigits[Range[3000], 2], SequenceCount[#, {0, 0}] == 0 &]; t = Total[# * Reverse @ LucasL[Range[0, Length[#] - 1]]] & /@ lazy; s = FromDigits /@ lazy[[TakeWhile[Flatten[FirstPosition[t, #] & /@ Range[Max[t]]], NumberQ]]]; Position[Divisible[Range[Length[s]], Plus @@@ IntegerDigits[s]], True] // Flatten
Showing 1-5 of 5 results.