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.

A098290 Recurrence sequence based on positions of digits in decimal places of Zeta(3) (Apery's constant).

Original entry on oeis.org

0, 2, 1, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10, 208, 380, 394, 159, 10
Offset: 0

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Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 02 2004

Keywords

Comments

This recurrence sequence starts to repeat quite quickly because 1 appears at the 10th digit of Zeta(3), which is also where 159 starts.
Can the transcendental numbers such that recurrence relations of this kind eventually repeat be characterized? - Nathaniel Johnston, Apr 30 2011

Examples

			Zeta(3) = 1.2020569031595942853997...
a(0)=0, a(1)=2 because 2nd decimal = 0, a(2)=1 because first digit = 2, etc.
		

Crossrefs

Cf. A002117 for digits of Zeta(3). Other recurrence sequences: A097614 for Pi, A098266 for e, A098289 for log(2), A098290 for Zeta(3), A098319 for 1/Pi, A098320 for 1/e, A098321 for gamma, A098322 for G, A098323 for 1/G, A098324 for Golden Ratio (phi), A098325 for sqrt(Pi), A098326 for sqrt(2), A120482 for sqrt(3), A189893 for sqrt(5), A098327 for sqrt(e), A098328 for 2^(1/3).

Programs

  • Maple
    with(StringTools): Digits:=400: G:=convert(evalf(Zeta(3)-1), string): a[0]:=0: for n from 1 to 50 do a[n]:=Search(convert(a[n-1], string), G)-1:printf("%d, ", a[n-1]):od: # Nathaniel Johnston, Apr 30 2011

Formula

a(0)=0, p(i)=position of first occurrence of a(i) in decimal places of Zeta(3), a(i+1)=p(i).

A098326 Recurrence derived from the decimal places of sqrt(2). a(0)=0, a(i+1)=position of first occurrence of a(i) in decimal places of sqrt(2).

Original entry on oeis.org

0, 13, 5, 7, 11, 186, 239, 336, 1284, 5889, 11708, 70286, 19276, 35435, 22479, 42202, 28785, 107081, 973876, 1187108
Offset: 0

Views

Author

Mark Hudson (mrmarkhudson(AT)hotmail.com), Sep 13 2004

Keywords

Examples

			sqrt(2)=1.4142135623730950488...
So for example a(2)=13 because 13th decimal place of sqrt(2) is 0; then a(3)=5 because 13 is found starting at the 5th decimal place; a(4)=7 because 5 is at the 7th decimal place and so on.
		

Crossrefs

Other recurrence sequences: A097614 for Pi, A098266 for e, A098289 for log(2), A098290 for Zeta(3), A098319 for 1/Pi, A098320 for 1/e, A098321 for gamma, A098322 for G, A098323 for 1/G, A098324 for Golden Ratio (phi), A098325 for sqrt(Pi), A120482 for sqrt(3), A189893 for sqrt(5). A002193 for digits of sqrt(2).

Programs

  • Maple
    with(StringTools): Digits:=10000: G:=convert(evalf(sqrt(2)),string): a[0]:=0: for n from 1 to 10 do a[n]:=Search(convert(a[n-1],string), G)-2:printf("%d, ",a[n-1]):od: # Nathaniel Johnston, Apr 30 2011

Extensions

a(18)-a(19) from Nathaniel Johnston, Apr 30 2011

A189893 Recurrence sequence derived from the digits of the square root of 5 after its decimal point.

Original entry on oeis.org

0, 4, 10, 65, 173, 22, 96, 15, 48, 78, 13, 201, 487, 594, 2719, 5146, 8719, 11530, 15308, 76411, 76016, 42220, 67129, 45349, 170266, 255576, 457846, 865810, 1131083, 8045547, 7669757
Offset: 0

Views

Author

Nathaniel Johnston, Apr 30 2011

Keywords

Examples

			sqrt(5) = 2.2360679774997896964091736687...
So for example, with a(0) = 0, a(1) = 4 because the 4th digit after the decimal point is 0; a(2) = 10 because the 10th digit after the decimal point is 4 and so on.
		

Crossrefs

Other recurrence sequences: A097614 for Pi, A098266 for e, A098289 for log(2), A098290 for Zeta(3), A098319 for 1/Pi, A098320 for 1/e, A098321 for gamma, A098322 for G, A098323 for 1/G, A098324 for Golden Ratio (phi), A098325 for sqrt(Pi), A098326 for sqrt(2), A120482 for sqrt(3), A098327 for sqrt(e), A098328 for 2^(1/3).

Programs

  • Maple
    with(StringTools): Digits:=10000: G:=convert(evalf(sqrt(5)),string): a[0]:=0: for n from 1 to 17 do a[n]:=Search(convert(a[n-1],string), G)-2:printf("%d, ",a[n-1]):od:

Formula

a(0) = 0; for i >= 0, a(i+1) = position of first occurrence of a(i) in decimal places of sqrt(5).
Showing 1-3 of 3 results.