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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A382106 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372270.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Mar 27 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
5 | A372269, A372270 | A382106, this sequence

Examples

			0.236926885056189087514264040719917362643260002212...
		

Crossrefs

Cf. A372270.

Formula

Equals (322-13*sqrt(70))/900.

A382107 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372271.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Mar 27 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
6 | A372271, A372272, A372273 | this sequence, A382686, A382687

Examples

			0.4679139345726910473898703439895509948116556057692...
		

Crossrefs

Cf. A372271.

A382686 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372272.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Apr 03 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
6 | A372271, A372272, A372273 | A382107, this sequence, A382687

Examples

			0.36076157304813860756983351383771611166152189274674...
		

Crossrefs

Cf. A372272.

A382687 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372273.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Apr 03 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
6 | A372271, A372272, A372273 | A382107, A382686, this sequence

Examples

			0.17132449237917034504029614217273289352682250148404...
		

Crossrefs

Cf. A372273.

A382688 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372274.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Apr 03 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
7 | A372274, A372275, A372276 | this sequence, A382689, A382690

Examples

			0.3818300505051189449503697754889751338783650835338627...
		

Crossrefs

Cf. A372274.

A382689 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372275.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Apr 03 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
7 | A372274, A372275, A372276 | A382688, this sequence, A382690

Examples

			0.279705391489276667901467771423779582486925065226598764...
		

Crossrefs

Cf. A372275.

A382690 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372276.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Apr 03 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
7 | A372274, A372275, A372276 | A382688, A382689, this sequence

Examples

			0.12948496616886969327061143267908201832858740225994666...
		

Crossrefs

Cf. A372276.

A382105 Decimal expansion of the weight factor for Legendre-Gauss quadrature corresponding to abscissa A372269.

Original entry on oeis.org

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

Views

Author

A.H.M. Smeets, Mar 27 2025

Keywords

Comments

There are floor(k/2) positive zeros of the Legendre polynomial of degree k:
k | zeros | corresponding weights
---+---------------------------+--------------------------
2 | A020760 | A000007*10
3 | A010513/10 | A010716
5 | A372269, A372270 | this sequence, A382106

Examples

			0.47862867049936646804129151483563819291229555334...
		

Crossrefs

Cf. A372269.

Formula

Equals (322+13*sqrt(70))/900.

A010703 Period 2: repeat (3,5).

Original entry on oeis.org

3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5, 3, 5
Offset: 0

Views

Author

Keywords

Comments

From Klaus Brockhaus, Dec 10 2009: (Start)
Interleaving of A010701 and A010716.
Also continued fraction expansion of (15+sqrt(285))/10.
Also decimal expansion of 35/99.
Binomial transform of 3 followed by A084633 without initial terms 1,0.
Inverse binomial transform of A171497. (End)

Crossrefs

Cf. A010701 (all 3's sequence), A010716 (all 5's sequence), A084633 (inverse binomial transform of repeated odd numbers), A171497.

Programs

Formula

From Klaus Brockhaus, Dec 10 2009: (Start)
a(n) = a(n-2) for n > 1; a(0) = 3, a(1) = 5.
G.f.: (3+5*x)/((1-x)*(1+x)). (End)
a(n) = 4 - (-1)^n. - Aaron J Grech, Aug 02 2024
E.g.f.: 3*cosh(x) + 5*sinh(x). - Stefano Spezia, Aug 04 2024

A180138 Table, t, read by antidiagonals: t(b,e) is the smallest k such that k*b^e is a sum of two successive primes.

Original entry on oeis.org

5, 5, 4, 5, 4, 2, 5, 2, 2, 1, 5, 1, 7, 6, 7, 5, 2, 4, 2, 2, 4, 5, 6, 1, 10, 9, 10, 2, 5, 1, 18, 1, 2, 8, 20, 1, 5, 2, 2, 10, 4, 8, 2, 26, 9, 5, 3, 2, 15, 30, 12, 12, 25, 22, 15, 5, 18, 1, 20, 2, 18, 2, 12, 11, 10, 8, 5, 1, 6, 6, 22, 19, 4, 1, 36, 6, 16, 4, 5, 4, 1, 24, 6, 16, 6, 28, 4, 12, 10, 8, 2
Offset: 1

Views

Author

Keywords

Comments

1st row: A180130, 2nd row: A180131, 3rd row: bisection of A180130, 4th row: A180132, 5th row: A180133, 6th row: A180134, 7th row: trisection of A180130, 8th row: bisection of A180131, 9th row: A179975, 10th row: A180135, 11th row: A180136 and 12th row: A180137; 1st column: A010716.
The k-th term == 1 10, 12, 24, 30, 32, 36, 58, 68, 74, 81, 105, 155, 278, 303, 315, 331, 419, 437, 439, 632, 638, 752, 857, 863, 906, 924, 950, ..., .
Increasing terms: {5, 6, 10, 20, 26, 72, 104, 118, 306, 320, 348, 572, 824, 828, 972, 1054, 1110, 1540, 5, 7, 10, 18, 20, 26, 30, 36, 52, 66, 72, 120, 132, 168, 266, 574, 640, 776, 1600, 1938, 2616, 3124, 3306, 4440, ...,
which occurs at the k-th term: 5, 6, 10, 20, 26, 72, 104, 118, 306, 320, 348, 572, 824, 828, 972, 1054, 1110, 1540, 5, 7, 10, 18, 20, 26, 30, 36, 52, 66, 72, 120, 132, 168, 266, 574, 640, 776, 1600, 1938, 2616, 3124, 3306, 4440, 1, 13, 25, 31, 35, 44, 50, 75, 114, 117, 119, 166, 187, 267, 289, 615, 1416, 1575, 2069, 3463, 4840, 5968, 7709, 9695, ..., .
Increasing terms by antidiagonals: t(2,0)=5, t(4,2)=t(2,4)=7, t(5,3)=t(3,5)=10, t(3,6)=20, t(3,7)=26, t(7,4)=30, t(5,8)=36, t(3,13)=72, t(7,12)=120, t(5,15)=132, t(11,13)=168, t(13,12)=266, t(17,19)=574, t(17,37)=640, t(23,34)=776, t(13,52)=1600, t(25,59)=1938, t(13,86)=2616. t(29,81)=3124, t(43,82)=3306, t(37,103)=4440..., .
Corresponding primes are twin primes for t(18,2), t(24,2), t(54,6), t(60,5), t(72,6), t(102,8), t(114,1), t=(126,1), ..., .

Examples

			.\e..0...1...2...3...4...5...6...7...8...9..10..11..12..13..14..15..16..17..18..19..20..21..22..23..24..25
.b\
.2...5...4...2...1...7...4...2...1...9..15...8...4...2...1..25..19..11..12...6...3..10...5..35..33..52..26
.3...5...4...2...6...2..10..20..26..22..10..16...8...8..72..24...8..18...6...2...6...2..10..20..20..22..20
.4...5...2...7...2...9...8...2..25..11...6..10..35..52..13..14..15..19..47..13..84..21..35...9..23..49..52
.5...5...1...4..10...2...8..12..12..36..12..28..66..30...6..18.132..36.108..34..14..48..60..12..22.150..30
.6...5...2...1...1...4..12...2...1...4...3...5...8...7..34...8..11..33..26..13...9..13..90..15..40..30...5
.7...5...6..18..10..30..18...4..28...4..30..30..60.120..38..12...6..52.120..70..10.102..60..70..10.186.174
.8...5...1...2..15...2..19...6...5..52..28..15..45..13..42..35..46..49..26..24...3..18..15..21..62..32...4
.9...5...2...2..20..22..16...8..24..18...2...2..20..22..52.104..84..38.102.100..30.192..46..22..84.176..30
10...5...3...1...6...6...6..14...6...9..19..21..21..42..93..21...6..11...2..12.111..37..39..63..38..42..24
11...5..18...6..24...6..32..40..26..20..94..50..26..10.168..30..18.196.126..70.166..30..54.130..26..50..10
12...5...1...1...2..18...8..13...6...2..11..11..39..20..12...1...8...9..31.182..24...2.126.128..66...9..86
13...5...4..24...4...8..22..40...4..14..16..28..10.266..40..20..46.112.156..12..20.228..26...2.220..60.140
...
		

Crossrefs

Programs

  • Mathematica
    t[b_, e_] := Block[{k = 1, hnp = b^e/2}, While[ h = k*hnp; PrimeQ@h || NextPrime[h, -1] + NextPrime@h != 2 h, k++ ]; k]; Table[ t[b - e, e], {b, 2, 14}, {e, 0, b - 2}] // Flatten
    (* to find twins other than 2&3 *) gQ[b_, e_, k_] := Block[{h = k*b^e/2}, NextPrime@h - NextPrime[h, -1] < 3 ]; Do[ If[ gQ[b - e, e, k], Print[{b - e, e}]], {b, 2, 143}, {e, 0, b - 2}]
  • Python
    from sympy import isprime, nextprime, prevprime
    def sum2succ(n):
      if n <= 5: return n == 5
      return not isprime(n//2) and n == prevprime(n//2) + nextprime(n//2)
    def T(b, e):
      k, powb = 1, b**e
      while not sum2succ(k*powb): k += 1
      return k
    def atodiag(maxd): # maxd antidiagonals
      return [T(b-e, e) for b in range(2, maxd+2) for e in range(b-1)]
    print(atodiag(13)) # Michael S. Branicky, May 05 2021
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