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.

A242144 T(n,k)=Number of length n+5 0..k arrays with no consecutive six elements summing to more than 3*k.

Original entry on oeis.org

42, 435, 74, 2338, 1113, 132, 8688, 7862, 2902, 236, 25494, 36224, 27024, 7596, 421, 63490, 126894, 154647, 93308, 19834, 747, 140148, 367358, 647404, 663395, 321320, 51440, 1314, 282051, 924300, 2180310, 3319500, 2837837, 1098260, 131950, 2318
Offset: 1

Views

Author

R. H. Hardin, May 05 2014

Keywords

Comments

Table starts
...42....435....2338.....8688.....25494......63490......140148......282051
...74...1113....7862....36224....126894.....367358......924300.....2088459
..132...2902...27024...154647....647404....2180310.....6256170....15876783
..236...7596...93308...663395...3319500...13006484....42564898...121330981
..421..19834..321320..2837837..16970962...77357343...288712815...924335053
..747..51440.1098260.12043599..86052208..456215409..1941492045..6980495147
.1314.131950.3708268.50455611.430518585.2653766000.12874102578.51971761446

Examples

			Some solutions for n=3 k=4
..2....1....0....0....0....2....0....0....0....0....2....0....1....0....1....2
..1....0....0....3....3....3....3....0....3....2....2....4....3....3....0....1
..1....1....4....2....1....0....0....4....1....0....1....3....1....2....1....0
..4....3....0....2....1....1....3....2....0....2....1....0....0....0....0....1
..1....0....3....2....3....1....1....0....4....0....1....0....1....1....1....1
..1....0....1....0....0....2....4....1....1....0....4....2....4....3....2....4
..1....1....0....2....0....4....0....1....1....2....3....1....2....0....1....0
..1....2....3....3....2....1....1....3....3....1....1....2....0....1....2....3
		

Crossrefs

Column 1 is A133551(n+5)
Column 2 is A212227
Column 3 is A212466

Formula

Empirical for column k:
k=1: [linear recurrence of order 20]
Empirical for row n:
n=1: [polynomial of degree 6]
n=2: [polynomial of degree 7]
n=3: [polynomial of degree 8]
n=4: [polynomial of degree 9]
n=5: [polynomial of degree 10]
n=6: [polynomial of degree 11]
n=7: [polynomial of degree 12]

A212402 T(n,k)=Number of binary arrays of length n+2*k-1 with no more than k ones in any length 2k subsequence (=50% duty cycle).

Original entry on oeis.org

3, 11, 5, 42, 19, 8, 163, 74, 33, 13, 638, 291, 132, 57, 21, 2510, 1150, 527, 236, 97, 34, 9908, 4558, 2104, 959, 421, 166, 55, 39203, 18100, 8402, 3872, 1747, 747, 285, 89, 155382, 71971, 33560, 15586, 7143, 3179, 1314, 489, 144, 616666, 286454, 134075
Offset: 1

Views

Author

R. H. Hardin May 14 2012

Keywords

Comments

Table starts
..3..11...42...163...638...2510...9908...39203...155382...616666...2449868
..5..19...74...291..1150...4558..18100...71971...286454..1140954...4547020
..8..33..132...527..2104...8402..33560..134075...535728..2140910...8556568
.13..57..236...959..3872..15586..62632..251419..1008536..4043582..16206152
.21..97..421..1747..7143..29002.117290..473171..1905675..7665886..30810054
.34.166..747..3179.13185..54042.220054..892387..3609005.14567294..58714842
.55.285.1314..5769.24322.100736.413220.1685039..6844362.27724036.112072540
.89.489.2318.10425.44794.187696.776116.3183631.12990818.52815156.214150732

Examples

			Some solutions for n=3 k=4
..0....0....0....1....0....0....0....0....1....1....1....0....1....0....1....1
..1....0....1....1....0....0....1....0....1....1....0....1....1....1....0....0
..1....1....1....0....1....0....1....0....1....0....1....0....0....0....0....0
..0....1....1....0....1....0....1....0....0....1....0....1....1....0....1....0
..1....0....0....0....1....1....1....1....0....0....1....0....0....1....0....0
..0....0....0....1....0....1....0....0....0....0....0....0....0....0....1....0
..0....0....0....0....0....0....0....0....0....0....0....0....0....1....1....1
..0....1....1....0....0....1....0....1....0....1....1....0....1....0....0....1
..0....0....0....1....0....1....0....1....1....1....1....1....0....0....0....1
..1....0....0....1....1....0....0....0....1....1....0....1....0....0....1....1
		

Crossrefs

Column 1 is A000045(n+3)
Column 2 is A118647(n+3)
Column 3 is A133551(n+5)
Row 1 is A032443

A120118 a(n) is the number of binary strings of length n such that no subsequence of length 5 or less contains 3 or more ones.

Original entry on oeis.org

1, 2, 4, 7, 11, 16, 26, 43, 71, 116, 186, 300, 487, 792, 1287, 2087, 3382, 5484, 8898, 14438, 23423, 37993, 61625, 99965, 162165, 263065, 426736, 692229, 1122903, 1821538, 2954849, 4793266, 7775472, 12613097, 20460538, 33190414, 53840404
Offset: 0

Views

Author

Tanya Khovanova, Aug 15 2006, Oct 11 2006

Keywords

Examples

			This sequence is similar to A118647 - where no subsequence of length 4 contains 3 ones. It is obvious that the first 4 terms of these two sequences are the same. There are only 3 sequences of length 5 that contain 3 ones such that no subsequence of length 4 contains 3 ones: 10101, 11001, 10011. Hence the fifth term for this sequence is 3 less than the corresponding term of A118647.
		

Crossrefs

Programs

  • Magma
    R:=PowerSeriesRing(Integers(), 40); Coefficients(R!( 1 +x*(1 +x+x^2)*(2+x^2+x^3-x^4-x^5-x^7)/(1-x-x^3-2*x^5+x^8+x^10) )); // G. C. Greubel, May 05 2023
    
  • Mathematica
    LinearRecurrence[{1,0,1,0,2,0,0,-1,0,-1}, {1,2,4,7,11,16,26,43,71,116, 186}, 50] (* Harvey P. Dale, Nov 27 2013 *)
  • SageMath
    def A120118_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P( 1 +x*(1+x+x^2)*(2+x^2+x^3-x^4-x^5-x^7)/(1-x-x^3-2*x^5 +
         x^8+x^10) ).list()
    A120118_list(40) # G. C. Greubel, May 05 2023

Formula

a(n) = a(n-1) + a(n-3) + 2*a(n-5) - a(n-8) - a(n-10).
G.f.: 1 + x*(1+x+x^2)*(2+x^2+x^3-x^4-x^5-x^7)/(1-x-x^3-2*x^5+x^8+x^10). - R. J. Mathar, Nov 28 2011

A133548 a(n) = sum of cubes of first n odd primes.

Original entry on oeis.org

27, 152, 495, 1826, 4023, 8936, 15795, 27962, 52351, 82142, 132795, 201716, 281223, 385046, 533923, 739302, 966283, 1267046, 1624957, 2013974, 2507013, 3078800, 3783769, 4696442, 5726743, 6819470, 8044513, 9339542, 10782439, 12830822, 15078913, 17650266
Offset: 1

Views

Author

Artur Jasinski, Sep 16 2007, corrected Jun 08 2008

Keywords

Examples

			a(3)=495 because 3^3+5^3+7^3=495.
		

Crossrefs

Programs

  • Mathematica
    c = 3; a = {}; b = 0; Do[b = b + Prime[n]^c; AppendTo[a, b], {n, 2, 1000}]; a
    Accumulate[Prime[Range[2,40]]^3] (* Harvey P. Dale, Oct 31 2024 *)
  • PARI
    a(n) = sum(i=2, n+1, prime(i)^3); \\ Michel Marcus, Nov 05 2013

Formula

a(n) = A098999(n+1) - 8.

Extensions

More terms from Michel Marcus, Nov 05 2013

A133550 Sum of fifth powers of n odd primes.

Original entry on oeis.org

243, 3368, 20175, 181226, 552519, 1972376, 4448475, 10884818, 31395967, 60025118, 129369075, 245225276, 392233719, 621578726, 1039774219, 1754698518, 2599294819, 3949419926, 5753649277, 7826720870, 10903777269, 14842817912
Offset: 1

Views

Author

Artur Jasinski, Sep 16 2007

Keywords

Examples

			a(2)=3368 because 3^5+5^5 = 3368.
		

Crossrefs

Programs

  • Mathematica
    c = 5; a = {}; b = 0; Do[b = b + Prime[n]^c; AppendTo[a, b], {n, 2, 1000}]; a

Formula

a(n) = A122103(n+1)-32.

A335247 a(n) is the number of binary (0,1) sequences of length n that have at least two ones in each window of eight consecutive symbols.

Original entry on oeis.org

1, 2, 4, 8, 16, 32, 64, 127, 247, 487, 961, 1897, 3745, 7393, 14593, 28801, 56833, 112156, 221341, 436825, 862094, 1701380, 3357739, 6626611, 13077820, 25809478, 50935832, 100523529, 198386490, 391522260, 772682018, 1524913233, 3009466064, 5939279536, 11721362180
Offset: 0

Views

Author

Kees Immink, May 28 2020

Keywords

Comments

Application: Not all electronic devices connected to the Internet of Things (IoT) have batteries or are connected to the power cable. These self-contained devices must rely on the harvesting of energy of the signals sent by a transmitter. A minimal number of 1's in transmitted sequences is required so as to carry sufficient energy within a prescribed time span. A binary sequence is said to obey the sliding-window (ell,t)-constraint if the number of 1's within any window of ell consecutive bits of that sequence is at least t, t

Crossrefs

Programs

  • Mathematica
    CoefficientList[Series[-(x^27 +x^26 -x^23 -x^22 -3*x^19 -5*x^18 -3*x^17 +3*x^15 +4*x^14 +2*x^13 +3*x^11 +5*x^10 +5*x^9 +3*x^8 -3*x^7 -3*x^6 -2*x^5 -x^4 -x^3 -x^2 -x -1) / (x^28 -x^24 -3*x^20 -3*x^19 +3*x^16 +2*x^15 +3*x^12 +4*x^11 +3*x^10 -3*x^8 -2*x^7 -x^6 -x^4 -x^3 -x^2 -x +1),{x,0,100}],x] (* Georg Fischer, Oct 26 2020 *)
    LinearRecurrence[{1,1,1,1,0,1,2,3,0,-3,-4,-3,0,0,-2,-3,0,0,3,3,0,0,0,1,0,0,0,-1},{1,2,4,8,16,32,64,127,247,487,961,1897,3745,7393,14593,28801,56833,112156,221341,436825,862094,1701380,3357739,6626611,13077820,25809478,50935832,100523529},40] (* Harvey P. Dale, Feb 21 2022 *)

Formula

G.f.: -(x^27+x^26-x^23-x^22-3*x^19-5*x^18-3*x^17+3*x^15+4*x^14+2*x^13 +3*x^11 +5*x^10+5*x^9+3*x^8-3*x^7-3*x^6-2*x^5-x^4-x^3-x^2-x-1) / (x^28-x^24-3*x^20 -3*x^19 +3*x^16 +2*x^15+3*x^12+4*x^11+3*x^10-3*x^8-2*x^7-x^6-x^4-x^3-x^2-x+1).
a(n) = a(n-1)+a(n-2)+a(n-3)+a(n-4)+a(n-6)+2*a(n-7)+3*a(n-8)-3*a(n-10) -4*a(n-11) -3*a(n-12) -2*a(n-15)-3*a(n-16)+3*a(n-19)+3*a(n-20)+a(n-24)-a(n-28), n>28.
a(n) ~ c*r^n where c = 1.07317641333 and r = 1.9735326811117101072.

A133549 Sum of the fourth powers of the first n odd primes.

Original entry on oeis.org

81, 706, 3107, 17748, 46309, 129830, 260151, 539992, 1247273, 2170794, 4044955, 6870716, 10289517, 15169198, 23059679, 35177040, 49022881, 69174002, 94585683, 122983924, 161934005, 209392326, 272134567, 360663848, 464724249, 577275130
Offset: 1

Author

Artur Jasinski, Sep 16 2007

Keywords

Examples

			a(2)=706 because 3^4 + 5^4 = 706.
		

Programs

  • Maple
    a:=proc (n) options operator, arrow: add(ithprime(j)^4, j=2..n+1) end proc: seq(a(n),n=1..26); # Emeric Deutsch, Oct 02 2007
  • Mathematica
    c = 4; a = {}; b = 0; Do[b = b + Prime[n]^c; AppendTo[a, b], {n, 2, 1000}]; a

Formula

a(n) = A122102(n+1) - 16. - Michel Marcus, Nov 05 2013

Extensions

Comment corrected by Michel Marcus, Nov 05 2013
Showing 1-7 of 7 results.