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 1-7 of 7 results.

A364185 Leading digit of 11^n.

Original entry on oeis.org

1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 6, 7, 8, 8, 9, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 6, 6, 7, 8, 8, 9, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 6, 7, 7, 8, 9, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 7, 7, 8, 9, 1, 1, 1, 1
Offset: 0

Views

Author

Seiichi Manyama, Jul 15 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := IntegerDigits[11^n][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jul 15 2023 *)
  • PARI
    a(n) = digits(11^n)[1];

Formula

a(n) = A000030(A001020(n)).

A111395 First digit of powers of 5.

Original entry on oeis.org

1, 5, 2, 1, 6, 3, 1, 7, 3, 1, 9, 4, 2, 1, 6, 3, 1, 7, 3, 1, 9, 4, 2, 1, 5, 2, 1, 7, 3, 1, 9, 4, 2, 1, 5, 2, 1, 7, 3, 1, 9, 4, 2, 1, 5, 2, 1, 7, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6, 3, 1, 8, 4, 2, 1, 5, 2, 1, 6
Offset: 0

Views

Author

Almerio A. Castro (almerio.castro(AT)gmail.com), Nov 11 2005

Keywords

Crossrefs

Programs

  • Mathematica
    First[IntegerDigits[#]]&/@(5^Range[0,100]) (* Harvey P. Dale, Jan 13 2015 *)
  • PARI
    a(n) = digits(5^n)[1]; \\ Michel Marcus, Jan 07 2014

Formula

a(n) = A000030(A000351(n)). - Seiichi Manyama, Jul 15 2023

Extensions

a(0)=1 prepended, and more terms from Michel Marcus, Jan 07 2014

A363249 Leading digit of 9^n.

Original entry on oeis.org

1, 9, 8, 7, 6, 5, 5, 4, 4, 3, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 9, 8, 7, 7, 6, 5, 5, 4, 4, 3, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 9, 8, 7, 7, 6, 5, 5, 4, 4, 3, 3, 3, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 9, 8, 7, 6, 6, 5, 5, 4, 4, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 9, 8, 7, 6, 6, 5, 4, 4, 4, 3, 3, 2, 2
Offset: 0

Views

Author

Seiichi Manyama, Jul 15 2023

Keywords

References

  • He, Xinwei; Hildebrand, A J; Li, Yuchen; Zhang, Yunyi, Complexity of Leading Digit Sequences, Discrete Mathematics and Theoretical Computer Science; 22 (2020), #14.

Crossrefs

Programs

  • Mathematica
    a[n_] := IntegerDigits[9^n][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jul 15 2023 *)
  • PARI
    a(n) = digits(9^n)[1];

Formula

a(n) = A000030(A001019(n)).
a(n) = A060956(2*n).

A362871 Leading digit of 6^n.

Original entry on oeis.org

1, 6, 3, 2, 1, 7, 4, 2, 1, 1, 6, 3, 2, 1, 7, 4, 2, 1, 1, 6, 3, 2, 1, 7, 4, 2, 1, 1, 6, 3, 2, 1, 7, 4, 2, 1, 1, 6, 3, 2, 1, 8, 4, 2, 1, 1, 6, 3, 2, 1, 8, 4, 2, 1, 1, 6, 3, 2, 1, 8, 4, 2, 1, 1, 6, 3, 2, 1, 8, 4, 2, 1, 1, 6, 3, 2, 1, 8, 4, 2, 1, 1, 6, 3, 2, 1, 8, 5, 3, 1, 1, 6, 3, 2, 1, 8, 5, 3, 1, 1, 6
Offset: 0

Views

Author

Seiichi Manyama, Jul 15 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := IntegerDigits[6^n][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jul 15 2023 *)
  • PARI
    a(n) = digits(6^n)[1];

Formula

a(n) = A000030(A000400(n)).

A363093 Leading digit of 7^n.

Original entry on oeis.org

1, 7, 4, 3, 2, 1, 1, 8, 5, 4, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 8, 6, 4, 3, 2, 1, 1, 7, 5, 3, 2, 1, 1, 8, 5, 4, 2, 2, 1, 1, 7, 4, 3, 2, 1, 1, 8, 5, 4, 2, 1, 1, 9, 6, 4, 3, 2, 1, 1, 8, 5, 3, 2, 1, 1, 9, 6, 4, 3
Offset: 0

Views

Author

Seiichi Manyama, Jul 15 2023

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_] := IntegerDigits[7^n][[1]]; Array[a, 100, 0] (* Amiram Eldar, Jul 15 2023 *)
  • PARI
    a(n) = digits(7^n)[1];

Formula

a(n) = A000030(A000420(n)).

A138028 The array of the most significant digit of n^k read by antidiagonals.

Original entry on oeis.org

1, 1, 1, 1, 2, 1, 1, 3, 4, 1, 1, 4, 9, 8, 1, 1, 5, 1, 2, 1, 1, 1, 6, 2, 6, 8, 3, 1, 1, 7, 3, 1, 2, 2, 6, 1, 1, 8, 4, 2, 6, 1, 7, 1, 1, 1, 9, 6, 3, 1, 3, 4, 2, 2, 1, 1, 1, 8, 5, 2, 7, 1, 1, 6, 5, 1, 1, 1, 1, 7, 4, 1, 4, 7, 6, 1, 1, 1, 1, 1, 1, 1, 6, 3, 1, 2, 3, 2, 5, 2, 1, 1, 1, 1, 1, 1, 5, 2, 8, 1, 1, 1, 1, 4, 1
Offset: 1

Views

Author

Robert G. Wilson v, Feb 10 2008

Keywords

Examples

			n\k
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... .
1, 2, 4, 8, 1, 3, 6, 1, 2, 5, 1, 2, 4, 8, 1, 3, 6, 1, 2, 5, 1, ... .
1, 3, 9, 2, 8, 2, 7, 2, 6, 1, 5, 1, 5, 1, 4, 1, 4, 1, 3, 1, 3, ... .
1, 4, 1, 6, 2, 1, 4, 1, 6, 2, 1, 4, 1, 6, 2, 1, 4, 1, 6, 2, 1, ... .
1, 5, 2, 1, 6, 3, 1, 7, 3, 1, 9, 4, 2, 1, 6, 3, 1, 7, 3, 1, 9, ... .
1, 6, 3, 2, 1, 7, 4, 2, 1, 1, 6, 3, 2, 1, 7, 4, 2, 1, 1, 6, 3, ... .
1, 8, 6, 5, 4, 3, 2, 2, 1, 1, 1, 8, 6, 5, 4, 3, 2, 2, 1, 1, 1, ... .
1, 9, 8, 7, 6, 5, 5, 4, 4, 3, 3, 3, 2, 2, 2, 2, 1, 1, 1, 1, 1, ... .
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, ... .
1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 4, 4, 5, 5, 6, 6, ... .
1, 1, 1, 1, 2, 2, 2, 3, 4, 5, 6, 7, 8, 1, 1, 1, 1, 2, 2, 3, 3, ... .
......................................................................
		

Crossrefs

Programs

  • Mathematica
    f[n_, k_] := Quotient[n^k, 10^Floor[k*Log[10, n]]]; Table[f[ n - k, k], {n, 14}, {k, 0, n - 1}] // Flatten

A134468 Numbers n such that 2^n and 3^n have the same leading digit.

Original entry on oeis.org

0, 17, 28, 34, 40, 51, 57, 68, 80, 84, 85, 91, 97, 103, 107, 108, 114, 120, 125, 130, 142, 143, 147, 154, 159, 170, 176, 182, 187, 193, 199, 204, 206, 210, 216, 227, 233, 244, 250, 256, 260, 261, 267, 273, 278, 283, 284, 296, 301, 307, 318, 319, 323, 324, 330
Offset: 1

Views

Author

Lekraj Beedassy, Jan 20 2008

Keywords

Crossrefs

Programs

  • Maple
    A000030 := proc(n) op(-1, convert(n,base,10)) ; end: isA134468 := proc(n) if A000030(2^n) = A000030(3^n) then true ; else false; fi ; end: for n from 0 to 800 do if isA134468(n) then printf("%d, ",n) ; fi ; od: # R. J. Mathar, Jan 30 2008
  • Mathematica
    Select[Range[0, 500], IntegerDigits[2^# ][[1]] == IntegerDigits[3^# ][[1]] &] (* Stefan Steinerberger, Jan 21 2008 *)

Extensions

More terms from Stefan Steinerberger, Jan 21 2008
More terms from R. J. Mathar, Jan 30 2008
Showing 1-7 of 7 results.