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.

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A254335 Powers of 5 in base 60, concatenating the decimal values of the sexagesimal digits.

Original entry on oeis.org

1, 5, 25, 205, 1025, 5205, 42025, 214205, 1483025, 9023205, 45124025, 346032205, 1850165025, 13411241205, 75057010025, 391445050205, 3161345251025, 16210847055205, 121454355292025, 648483937264205, 3404031807133025, 25020163036073205, 141141223300374025, 1105826524503082205, 5545214234515415025
Offset: 0

Views

Author

Michael De Vlieger, Jan 28 2015

Keywords

Comments

Each sexagesimal digit appears as a pair of decimal digits as on a digital clock. Any leading zeros are truncated. Thus decimal 125 appears as "205" and not "0205".

Examples

			a(4) = 1025, since 5^4 = 625 = 10 * 60^1 + 25, thus 10:25 in clock-like notation, which becomes 1025 when restricted to numeric characters.
		

Crossrefs

Cf. A000351 (Powers of 5), A055643 (Babylonian numbers).
Cf. Sexagesimal representations: A250073 (Powers of 2), A254334 (Powers of 3), A254336 (Powers of 10).

Programs

  • Mathematica
    f[n_] := FromDigits@ StringJoin[If[# < 10, StringJoin["0", ToString[#]],
    ToString[#]] & /@ IntegerDigits[5^n, 60]]; Table[f@ i, {i, 0, 24}] (* Michael De Vlieger, Jan 28 2015 *)
  • PARI
    a(n) = subst(Pol(digits(5^n, 60)), x, 100); \\ Michel Marcus, Feb 22 2015

Formula

a(n) = A055643(A000351(n)). - Michel Marcus, Mar 02 2015

A254336 Powers of 10 in base 60, concatenating the decimal values of the sexagesimal digits.

Original entry on oeis.org

1, 10, 140, 1640, 24640, 274640, 4374640, 46174640, 742574640, 11709374640, 125136174640, 2083602574640, 21260029374640, 334200456174640, 3543204922574640, 55713281349374640, 593214421816174640, 9552227030242574640, 139134430302709374640, 1632172505043136174640, 24522541050451602574640
Offset: 0

Views

Author

Michael De Vlieger, Jan 28 2015

Keywords

Comments

Each sexagesimal digit appears as a pair of decimal digits as on a digital clock. Any leading zeros are truncated. Thus decimal 100 appears as "140" and not "0140".

Examples

			a(3) = 1640, since 10^3 = 1000 = 16 * 60^1 + 40, thus 16:40 in clock-like notation, which becomes 1640 when restricted to numeric characters.
		

Crossrefs

Cf. A011557 (Powers of 10), A055643 (Babylonian numbers).
Cf. Sexagesimal representations: A250073 (Powers of 2), A254334 (Powers of 3), A254335 (Powers of 5).

Programs

  • Mathematica
    f[n_] := FromDigits@ StringJoin[If[# < 10, StringJoin["0", ToString[#]],
    ToString[#]] & /@ IntegerDigits[10^n, 60]]; Table[f@ i, {i, 0, 20}] (* Michael De Vlieger, Jan 28 2015 *)
  • PARI
    a(n) = subst(Pol(digits(10^n, 60)), x, 100); \\ Michel Marcus, Feb 22 2015

Formula

a(n) = A055643(A011557(n)). - Michel Marcus, Mar 02 2015

A091722 Babylonian sexagesimal (base 60) expansion of 1/13.

Original entry on oeis.org

4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55, 23, 4, 36, 55
Offset: 0

Views

Author

Jeppe Stig Nielsen, Feb 01 2004

Keywords

Crossrefs

Programs

A281863 Alternating powers of 60 and 10 times powers of 60.

Original entry on oeis.org

1, 10, 60, 600, 3600, 36000, 216000, 2160000, 12960000, 129600000, 777600000, 7776000000, 46656000000, 466560000000, 2799360000000, 27993600000000, 167961600000000, 1679616000000000, 10077696000000000, 100776960000000000, 604661760000000000
Offset: 0

Views

Author

Wolfdieter Lang, Feb 19 2017

Keywords

Comments

These numbers are the values for the positions in the Sumerian (and Babylonian) alternating sexagesimal - decimal system (used at least up to 10*60^2 = 36000, but here extended).
For the numbers in this mixed base system see A055643. For the number of symbols needed for representing n see A131650. For the number of digits (including 0) of the representation of n see A282622.

References

  • Georges Ifrah, Histoire Universelle des Chiffres, Paris, 1981.
  • Georges Ifrah, From one to zero, A universal history of numbers, Viking Penguin Inc., 1985.
  • Georges Ifrah, Universalgeschichte der Zahlen, Campus Verlag, Frankfurt, New York, 2. Auflage, 1987, pp. 210-221.
  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers. Penguin Books, NY, 1986, Revised edition 1987. See p. 127.

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{0,60},{1,10},21] (* or *) a[0]=1;a[1]=10;a[n_]:=60*a[n-2];Table[a[n],{n,0,20}] (* Indranil Ghosh, Feb 21 2017 *)
  • PARI
    Vec((1 + 10*x) / (1 - 60*x^2) + O(x^30)) \\ Colin Barker, Feb 21 2017

Formula

a(2*n) = 60^(n/2), a(2*n+1) = 10*60^((n-1)/2), n >= 0.
From Colin Barker, Feb 21 2017: (Start)
a(n) = 60*a(n-2) for n>1.
G.f.: (1 + 10*x) / (1 - 60*x^2). (End)
E.g.f.: cosh(2*sqrt(15)*x) + sqrt(5/3)*sinh(2*sqrt(15)*x). - Stefano Spezia, Sep 08 2024

A357996 a(n) is the number of times in the format hh:mm that can be represented in a 7-segment display by using only n segments (version A006942).

Original entry on oeis.org

1, 2, 4, 14, 25, 37, 70, 105, 123, 153, 186, 182, 156, 139, 119, 79, 35, 9, 1
Offset: 8

Views

Author

Stefano Spezia, Oct 23 2022

Keywords

Comments

Since 8 <= A357970(n) <= 26 the sequence is finite and begins with offset 8.

Crossrefs

Histogram of A357970.

Programs

  • Mathematica
    a055643[n_]:=FromDigits@ Apply[Join, PadLeft[#, 2] & /@ IntegerDigits@ IntegerDigits[n, 60]]; a006942[n_] := Plus @@ (IntegerDigits@ n /. {0 -> 6, 1 -> 2, 2 -> 5, 3 -> 5, 7 -> 3, 8 -> 7, 9 -> 6}); a[n_]:=a006942[a055643[n]]+6(4-Ceiling[Log10[a055643[n]+1]]); Table[Count[Join[{24},Array[a,1439]],n],{n,8,26}]

A357997 a(n) is the number of times in the format hh:mm that can be represented in a 7-segment display by using only n segments (version A010371).

Original entry on oeis.org

1, 0, 5, 10, 16, 35, 66, 88, 119, 166, 187, 177, 161, 154, 129, 81, 35, 9, 1
Offset: 8

Views

Author

Stefano Spezia, Oct 23 2022

Keywords

Comments

Since 8 <= A357971(n) <= 26 the sequence is finite and begins with offset 8.

Crossrefs

Histogram of A357971.

Programs

  • Mathematica
    a055643[n_]:=FromDigits@ Apply[Join, PadLeft[#, 2] & /@ IntegerDigits@ IntegerDigits[n, 60]]; a010371[n_] := Plus @@ (IntegerDigits@ n /. {0 -> 6, 1 -> 2, 2 -> 5, 3 -> 5, 7 -> 4, 8 -> 7, 9 -> 6}); a[n_]:=a010371[a055643[n]]+6(4-Ceiling[Log10[a055643[n]+1]]); Table[Count[Join[{24},Array[a,1439]],n],{n,8,26}]

A357998 a(n) is the number of times in the format hh:mm that can be represented in a 7-segment display by using only n segments (version A063720).

Original entry on oeis.org

1, 2, 4, 18, 25, 41, 96, 103, 133, 189, 188, 154, 158, 155, 95, 53, 19, 5, 1
Offset: 8

Views

Author

Stefano Spezia, Oct 23 2022

Keywords

Comments

Since 8 <= A357972(n) <= 26 the sequence is finite and begins with offset 8.

Crossrefs

Histogram of A357972.

Programs

  • Mathematica
    a055643[n_]:=FromDigits@ Apply[Join, PadLeft[#, 2] & /@ IntegerDigits@ IntegerDigits[n, 60]]; a063720[n_] := Plus @@ (IntegerDigits@ n /. {0 -> 6, 1 -> 2, 2 -> 5, 3 -> 5, 6 -> 5, 7 -> 3, 8 -> 7, 9 -> 5}); a[n_]:=a063720[a055643[n]]+6(4-Ceiling[Log10[a055643[n]+1]]);Table[Count[Join[{24},Array[a,1439]],n],{n,8,26}]

A357999 a(n) is the number of times in the format hh:mm that can be represented in a 7-segment display by using only n segments (version A074458).

Original entry on oeis.org

1, 0, 5, 12, 14, 41, 74, 87, 128, 185, 185, 162, 167, 159, 119, 67, 26, 7, 1
Offset: 8

Views

Author

Stefano Spezia, Oct 23 2022

Keywords

Comments

Since 8 <= A357973(n) <= 26 the sequence is finite and begins with offset 8.

Crossrefs

Histogram of A357973.

Programs

  • Mathematica
    a055643[n_]:=FromDigits@ Apply[Join, PadLeft[#, 2] & /@ IntegerDigits@ IntegerDigits[n, 60]]; a074458[n_] := Plus @@ (IntegerDigits@ n /. {0 -> 6, 1 -> 2, 2 -> 5, 3 -> 5, 7 -> 4, 8 -> 7, 9 -> 5}); a[n_]:=a074458[a055643[n]]+6(4-Ceiling[Log10[a055643[n]+1]]);Table[Count[Join[{24},Array[a,1439]],n],{n,8,26}]

A358000 a(n) is the number of times in the format hh:mm that can be represented in a 7-segment display by using only n segments (version A277116).

Original entry on oeis.org

1, 2, 4, 16, 25, 39, 82, 106, 126, 170, 190, 169, 154, 146, 111, 65, 26, 7, 1
Offset: 8

Views

Author

Stefano Spezia, Oct 23 2022

Keywords

Comments

Since 8 <= A357974(n) <= 26 the sequence is finite and begins with offset 8.

Crossrefs

Histogram of A357974.

Programs

  • Mathematica
    a055643[n_]:=FromDigits@ Apply[Join, PadLeft[#, 2] & /@ IntegerDigits@ IntegerDigits[n, 60]]; a277116[n_] := Plus @@ (IntegerDigits@ n /. {0 -> 6, 1 -> 2, 2 -> 5, 3 -> 5, 7 -> 3, 8 -> 7, 9 -> 5}); a[n_]:=a277116[a055643[n]]+6(4-Ceiling[Log10[a055643[n]+1]]);Table[Count[Join[{24},Array[a,1439]],n],{n,8,26}]

A091721 Babylonian sexagesimal (base 60) expansion of 1/11.

Original entry on oeis.org

5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21, 49, 5, 27, 16, 21
Offset: 0

Views

Author

Jeppe Stig Nielsen, Feb 01 2004

Keywords

Comments

Period 5: repeat [5, 27, 16, 21, 49]. - Wesley Ivan Hurt, May 25 2024

Crossrefs

Programs

  • Mathematica
    RealDigits[ 1/11, 60, 75] [[1]] (* Robert G. Wilson v, Feb 02 2004 *)
    CoefficientList[Series[(5 + 27 x + 16 x^2 + 21 x^3 + 49 x^4)/(1 - x^5), {x, 0, 40}], x] (* Wesley Ivan Hurt, May 25 2024 *)

Formula

From Wesley Ivan Hurt, May 25 2024: (Start)
a(n+5) = a(n).
G.f.: (5+27*x+16*x^2+21*x^3+49*x^4)/(1-x^5). (End)
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