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.

Previous Showing 11-16 of 16 results.

A217165 a(n) is the least value of k such that the decimal expansion of Fibonacci(k) contains n consecutive identical digits.

Original entry on oeis.org

0, 10, 49, 66, 118, 883, 2202, 6493, 62334, 135241, 353587, 1162507, 5155873, 7280413, 37356153
Offset: 1

Views

Author

V. Raman, Sep 27 2012

Keywords

Comments

a(16) > 42000000. - Paul Geneau de Lamarlière, Feb 04 2024
a(16) > 10^8. - Nick Hobson, Feb 09 2024

Crossrefs

Programs

  • C
    // See Links section.
  • Mathematica
    k = 0; Join[{0}, Table[While[d = IntegerDigits[Fibonacci[k]]; ! MemberQ[Partition[Differences[d], n - 1, 1], Table[0, {n - 1}]], k++]; k, {n, 2, 8}]] (* T. D. Noe, Oct 02 2012 *)
  • Python
    def A217165(n):
        if n == 1:
            return 0
        else:
            l, y, x = [str(d)*n for d in range(10)], 0, 1
            for m in range(1, 10**9):
                s = str(x)
                for k in l:
                    if k in s:
                        return m
                y, x = x, y+x
            return 'search limit reached'
    # Chai Wah Wu, Dec 17 2014
    

Extensions

a(10)-a(11) from Chai Wah Wu, Dec 17 2014
a(12)-a(15) from Paul Geneau de Lamarlière, Feb 04 2024

A217166 a(n) is the least value of k such that the decimal expansion of Lucas(k) contains n consecutive identical digits.

Original entry on oeis.org

0, 5, 36, 78, 112, 538, 3139, 6436, 17544, 82864, 328448, 1701593, 1701593, 8030342, 8030342, 77552742
Offset: 1

Views

Author

V. Raman, Sep 27 2012

Keywords

Comments

a(12) > 1512000. - Chai Wah Wu, Dec 17 2014
a(17) > 10^8. - Nick Hobson, Feb 02 2024

Crossrefs

Programs

  • C
    // See Links section.
  • Mathematica
    k = 0; Join[{0}, Table[While[d = IntegerDigits[LucasL[k]]; ! MemberQ[Partition[Differences[d], n - 1, 1], Table[0, {n - 1}]], k++]; k, {n, 2, 8}]] (* T. D. Noe, Oct 02 2012 *)
  • Python
    def A217166(n):
        if n == 1:
            return 0
        else:
            l, y, x = [str(d)*n for d in range(10)], 2, 1
            for m in range(1, 10**9):
                s = str(x)
                for k in l:
                    if k in s:
                        return m
                y, x = x, y+x
            return 'search limit reached'
    # Chai Wah Wu, Dec 17 2014
    

Extensions

a(11) from Chai Wah Wu, Dec 17 2014
a(12)-a(16) from Nick Hobson, Feb 02 2024

A217186 a(n) is the number of digits in the decimal representation of the smallest power of 3 that contains n consecutive identical digits.

Original entry on oeis.org

1, 6, 16, 16, 131, 257, 1014, 3684, 10875, 51142, 51142, 304989
Offset: 1

Views

Author

V. Raman, Sep 27 2012

Keywords

Comments

Number of digits in 3^k is equal to floor(1 + k*log_10(3)).

Crossrefs

Programs

  • Mathematica
    k = 0; Join[{1}, Table[While[d = IntegerDigits[3^k]; prt = Partition[Differences[d], n - 1, 1]; ! MemberQ[prt, Table[0, {n - 1}]], k++]; Length[d], {n, 2, 8}]] (* T. D. Noe, Oct 03 2012 *)
  • Python
    def A217186(n):
        l, x = [str(d)*n for d in range(10)], 1
        for m in range(10**9):
            s = str(x)
            for k in l:
                if k in s:
                    return len(s)
            x *= 3
        return 'search limit reached'
    # Chai Wah Wu, Dec 17 2014

Extensions

a(12) from Chai Wah Wu, Dec 17 2014

A238507 Smallest number m such that 3^m contains a string of n consecutive increasing integers in its decimal representation.

Original entry on oeis.org

0, 8, 20, 57, 332, 332, 6814, 7926, 16724, 200633
Offset: 1

Views

Author

Derek Orr, Feb 27 2014

Keywords

Examples

			8 is the smallest exponent such that 3^8 contains two consecutive increasing integers (3^8 = 6561).
20 is the smallest exponent such that 3^20 contains three consecutive increasing integers (3^20 = 3486784401).
		

Crossrefs

Programs

  • Python
    def StrInc(x):
      for n in range(10**5):
        count = 0
        i = 0
        string = str(3**n)
        if len(string) == x and x == 1:
          return n
        while i < len(string)-1:
          if int(string[i]) == int(string[i+1])-1:
            count += 1
            i += 1
          else:
            if count >= x-1:
              return n
            else:
              count = 0
              i += 1
        if count >= x-1:
          return n
    x = 1
    while x < 15:
      print(StrInc(x))
      x += 1

Extensions

a(8)-a(10) from Giovanni Resta, Mar 02 2014

A215783 The least k such that the decimal expansion of 3^k contains 9 consecutive n's.

Original entry on oeis.org

107189, 44152, 22791, 67449, 125406, 67390, 90785, 67448, 32311, 164065
Offset: 0

Views

Author

V. Raman, Aug 23 2012

Keywords

Examples

			3^107189 = 141...2860000000000209...483 (51143 decimal digits, 0's start at position 45713).
		

Crossrefs

A238508 Smallest number m such that 3^m contains a string of n consecutive decreasing integers in its decimal representation.

Original entry on oeis.org

0, 5, 13, 50, 213, 536, 536, 4582, 63202, 163984
Offset: 1

Views

Author

Derek Orr, Feb 27 2014

Keywords

Examples

			5 is the smallest exponent such that 3^5 contains two consecutive decreasing integers (3^5 = 243).
13 is the smallest exponent such that 3^13 contains three consecutive decreasing integers (3^13 = 1594323).
		

Crossrefs

Programs

  • Python
    def StrDec(x):
      for n in range(10**5):
        count = 0
        i = 0
        string = str(3**n)
        if len(string) == x and x == 1:
          return n
        while i < len(string)-1:
          if int(string[i]) == int(string[i+1])-1:
            count += 1
            i += 1
          else:
            if count >= x-1:
              return n
            else:
              count = 0
              i += 1
        if count >= x-1:
          return n
    x = 1
    while x < 15:
      print(StrDec(x))
      x += 1

Extensions

a(9)-a(10) from Giovanni Resta, Mar 02 2014
Previous Showing 11-16 of 16 results.