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 1-3 of 3 results.

A351718 Numbers whose binary and maximal Lucas representations are both palindromic.

Original entry on oeis.org

0, 3, 5, 17, 85, 107, 219, 1161, 1365, 1619, 2047, 4097, 6141, 19801, 25027, 68961, 91213, 134337, 1540157, 1804859, 11877549, 37696497, 44092437, 142710801, 548269377, 3387848595, 4073444175, 8226780335, 31029923047, 64662095631, 67947722943, 126590440407, 2145176968607
Offset: 1

Views

Author

Amiram Eldar, Feb 17 2022

Keywords

Examples

			The first 10 terms are:
   n   a(n)  A007088(a(n))    A130311(a(n))
   ----------------------------------------
   1     0               0                0
   2     3              11               11
   3     5             101              101
   4    17           10001            11111
   5    85         1010101        101101101
   6   107         1101011        111010111
   7   219        11011011      10110101101
   8  1161     10010001001   11011111111011
   9  1365     10101010101  101010101010101
  10  1619     11001010011  101111010111101
		

Crossrefs

Intersection of A006995 and A351717.

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]]]; Join[{0}, Select[Position[s, _?PalindromeQ] // Flatten, PalindromeQ[IntegerDigits[#, 2]] &]]

A352088 Numbers whose binary and minimal tribonacci representations are both palindromic.

Original entry on oeis.org

0, 1, 3, 5, 45, 2193, 7671, 35889, 53835, 74825, 3026205, 31953871, 86582437, 117169915, 128873391, 701373669, 868430067, 15262037703, 45305389845, 104484026691, 614071181169, 14894476590363, 24382189266573, 86808432666553, 869188423288227, 1352557858988953
Offset: 1

Views

Author

Amiram Eldar, Mar 04 2022

Keywords

Examples

			The first 5 terms are:
  n  a(n)  A007088(a(n))  A278038(a(n))
  -------------------------------------
  1     0              0              0
  2     1              1              1
  3     3             11             11
  4     5            101            101
  5    45         101101        1000001
		

Crossrefs

Intersection of A006995 and A352087.
Similar sequences: A095309, A331193, A331894, A351713, A351718.

Programs

  • Mathematica
    t[1] = 1; t[2] = 2; t[3] = 4; t[n_] := t[n] = t[n - 1] + t[n - 2] + t[n - 3]; tribPalQ[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]; PalindromeQ[FromDigits @ IntegerDigits[Total[2^(s - 1)], 2]]]; Join[{0}, Select[Range[1, 10^5, 2], PalindromeQ[IntegerDigits[#, 2]] && tribPalQ[#] &]]

A352106 Numbers whose binary and maximal tribonacci representations are both palindromic.

Original entry on oeis.org

0, 1, 3, 5, 7, 27, 51, 325, 2193, 3735, 23709, 35889, 53835, 589833, 1294265, 17291201, 80719769, 1274288105, 23157444917, 23635236877, 230684552043, 1218891196337, 1722894010643, 2544113575977, 93096801594005, 175482093541881, 256924005422487, 372295593308821
Offset: 1

Views

Author

Amiram Eldar, Mar 05 2022

Keywords

Examples

			The first 5 terms are:
   n  a(n)  A007088(a(n))  A352103(a(n))
   -  ----  -------------  -------------
   1     0              0              0
   2     1              1              1
   3     3             11             11
   4     5            101            101
   5     7            111            111
   6    27          11011          11111
   7    51         110011         111111
   8   325      101000101      111111111
   9  2193   100010010001  1001101011001
  10  3735   111010010111  1111111111111
		

Crossrefs

Intersection of A006995 and A352105.
Similar sequences: A095309, A331193, A331894, A351713, A351718, A352088.

Programs

  • Mathematica
    t[1] = 1; t[2] = 2; t[3] = 4; t[n_] := t[n] = t[n - 1] + t[n - 2] + t[n - 3]; trib[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]; IntegerDigits[Total[2^(s - 1)], 2]]; lazyTribPalQ[n_] := Module[{v = trib[n]}, nv = Length[v]; i = 1; While[i <= nv - 3, If[v[[i ;; i + 3]] == {1, 0, 0, 0}, v[[i ;; i + 3]] = {0, 1, 1, 1}; If[i > 3, i -= 4]]; i++]; i = Position[v, _?(# > 0 &)]; If[i == {}, True, PalindromeQ[FromDigits[v[[i[[1, 1]] ;; -1]]]]]]; Join[{0}, Select[Range[1, 10^5, 2], PalindromeQ[IntegerDigits[#, 2]] && lazyTribPalQ[#] &]]
Showing 1-3 of 3 results.