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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A010889 Simple periodic sequence: repeat 1,2,3,4,5,6,7,8,9,10.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 1
Offset: 0

Views

Author

Keywords

Comments

Partial sums are given by A130488(n)+n+1. - Hieronymus Fischer, Jun 08 2007
Continued fraction expansion of (232405+sqrt(71216963807))/348378. [From Klaus Brockhaus, May 15 2010]

Crossrefs

Cf. A177933 (decimal expansion of (232405+sqrt(71216963807))/348378). [From Klaus Brockhaus, May 15 2010]

Programs

  • Mathematica
    PadRight[{},120,Range[10]] (* Harvey P. Dale, Feb 22 2015 *)
  • Python
    def a(n): return n % 10 + 1 # Paul Muljadi, Aug 06 2024

Formula

a(n) = 1 + (n mod 10) - Paolo P. Lava, Nov 21 2006
From Hieronymus Fischer, Jun 08 2007: (Start)
a(n) = A010879(n)+1.
G.f.: (Sum_{k=0..9} (k+1)*x^k)/(1-x^10).
G.f.: (10x^11-11x^10+1)/((1-x^10)(1-x)^2). (End)

Extensions

More terms from Klaus Brockhaus, May 15 2010

A130490 a(n) = Sum_{k=0..n} (k mod 12) (Partial sums of A010881).

Original entry on oeis.org

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 66, 67, 69, 72, 76, 81, 87, 94, 102, 111, 121, 132, 132, 133, 135, 138, 142, 147, 153, 160, 168, 177, 187, 198, 198, 199, 201, 204, 208, 213, 219, 226, 234, 243, 253, 264, 264, 265, 267, 270, 274, 279, 285, 292, 300
Offset: 0

Views

Author

Hieronymus Fischer, May 31 2007

Keywords

Comments

Let A be the Hessenberg n X n matrix defined by: A[1,j] = j mod 12, A[i,i]:=1, A[i,i-1]=-1. Then, for n >= 1, a(n)=det(A). - Milan Janjic, Jan 24 2010

Crossrefs

Programs

  • GAP
    List([0..60], n-> Sum([0..n], k-> k mod 12 )); # G. C. Greubel, Sep 01 2019
  • Magma
    [&+[(k mod 12): k in [0..n]]: n in [0..60]]; // G. C. Greubel, Sep 01 2019
    
  • Maple
    seq(coeff(series(x*(1-12*x^11+11*x^12)/((1-x^12)*(1-x)^3), x, n+1), x, n), n = 0..60); # G. C. Greubel, Sep 01 2019
  • Mathematica
    Sum[Mod[k, 12], {k, 0, Range[0, 60]}] (* G. C. Greubel, Sep 01 2019 *)
    LinearRecurrence[{1,0,0,0,0,0,0,0,0,0,0,1,-1},{0,1,3,6,10,15,21,28,36,45,55,66,66},60] (* Harvey P. Dale, Jan 16 2024 *)
  • PARI
    a(n) = sum(k=0, n, k % 12); \\ Michel Marcus, Apr 29 2018
    
  • Sage
    [sum(k%12 for k in (0..n)) for n in (0..60)] # G. C. Greubel, Sep 01 2019
    

Formula

a(n) = 66*floor(n/12) + A010881(n)*(A010881(n) + 1)/2.
G.f.: (Sum_{k=1..11} k*x^k)/((1-x^12)*(1-x)).
G.f.: x*(1 - 12*x^11 + 11*x^12)/((1-x^12)*(1-x)^3).

A204671 a(n) = n^n (mod 6).

Original entry on oeis.org

1, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4, 3, 4, 5, 0, 1, 4
Offset: 0

Views

Author

Keywords

Comments

For n>0, periodic with period 6 = A174824: repeat [1, 4, 3, 4, 5, 0].

Crossrefs

Programs

  • Magma
    [1] cat &cat [[1, 4, 3, 4, 5, 0]^^20]; // Wesley Ivan Hurt, Jun 23 2016
    
  • Maple
    A204671:=n->[1, 4, 3, 4, 5, 0][(n mod 6)+1]: 1, seq(A204671(n), n=0..100); # Wesley Ivan Hurt, Jun 23 2016
  • Mathematica
    Table[PowerMod[n,n,6], {n,0,140}]
    Join[{1},LinearRecurrence[{0, 0, 0, 0, 0, 1},{1, 4, 3, 4, 5, 0},86]] (* Ray Chandler, Aug 26 2015 *)
  • PARI
    a(n)=lift(Mod(n, 6)^n) \\ Andrew Howroyd, Feb 25 2018

Formula

G.f.: (x^6-5*x^5-4*x^4-3*x^3-4*x^2-x-1)/((x-1)*(x+1)*(x^2-x+1)*(x^2+x+1)). [Colin Barker, Jul 20 2012]
From Wesley Ivan Hurt, Jun 23 2016: (Start)
a(n) = a(n-6) for n>5.
a(0) = 1, a(n) = (17 - cos(n*Pi) - 8*cos(n*Pi/3) - 8*cos(2*n*Pi/3) - 4*sqrt(3)*sin(n*Pi/3) - 4*sqrt(3)*sin(2*n*Pi/3))/6 for n>0. (End)
a(n) = A010875(A000312(n)). - Michel Marcus, Jun 27 2016

A319707 Filter sequence which records for primes their residue modulo 6, and for all other numbers assigns a unique number.

Original entry on oeis.org

1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 5, 11, 7, 12, 13, 14, 5, 15, 7, 16, 17, 18, 5, 19, 20, 21, 22, 23, 5, 24, 7, 25, 26, 27, 28, 29, 7, 30, 31, 32, 5, 33, 7, 34, 35, 36, 5, 37, 38, 39, 40, 41, 5, 42, 43, 44, 45, 46, 5, 47, 7, 48, 49, 50, 51, 52, 7, 53, 54, 55, 5, 56, 7, 57, 58, 59, 60, 61, 7, 62, 63, 64, 5, 65, 66, 67, 68, 69, 5, 70, 71, 72, 73, 74, 75, 76, 7, 77, 78, 79, 5, 80, 7, 81, 82, 83, 5, 84, 7, 85, 86, 87, 5, 88, 89, 90, 91, 92, 93, 94, 95
Offset: 1

Views

Author

Antti Karttunen, Oct 04 2018

Keywords

Comments

Restricted growth sequence transform of function f defined as f(n) = A010875(n) when n is a prime, otherwise -n.
Primes of the form 6k+5 (A007528) get value 5, and the primes of the form 6k+1 (A002476) get value 7, while for all other n, a(n) is assigned to a unique running count.
For all i, j:
a(i) = a(j) => A010875(i) = A010875(j),
a(i) = a(j) => A305900(i) = A305900(j),
a(i) = a(j) => A319717(i) = A319717(j) => A319716(i) = A319716(j).

Crossrefs

Cf. A007528 (positions of 5's), A002476 (positions of 7's).
Cf. also A319704.
Differs from A319716 for the first time at n=121.

Programs

  • PARI
    up_to = 100000;
    rgs_transform(invec) = { my(om = Map(), outvec = vector(length(invec)), u=1); for(i=1, length(invec), if(mapisdefined(om,invec[i]), my(pp = mapget(om, invec[i])); outvec[i] = outvec[pp] , mapput(om,invec[i],i); outvec[i] = u; u++ )); outvec; };
    A319707aux(n) = if(isprime(n),(n%6),-n);
    v319707 = rgs_transform(vector(up_to,n,A319707aux(n)));
    A319707(n) = v319707[n];

A008670 Molien series for Weyl group F_4.

Original entry on oeis.org

1, 1, 1, 2, 3, 3, 5, 6, 7, 9, 11, 12, 16, 18, 20, 24, 28, 30, 36, 40, 44, 50, 56, 60, 69, 75, 81, 90, 99, 105, 117, 126, 135, 147, 159, 168, 184, 196, 208, 224, 240, 252, 272, 288, 304, 324, 344, 360, 385, 405, 425, 450, 475, 495, 525, 550, 575, 605, 635, 660, 696, 726, 756
Offset: 0

Views

Author

Keywords

Comments

Number of partitions of n into parts 1, 3, 4 and 6. - Ilya Gutkovskiy, May 24 2017

References

  • Coxeter and Moser, Generators and Relations for Discrete Groups, Table 10.
  • L. Smith, Polynomial Invariants of Finite Groups, Peters, 1995, p. 199 (No. 28).

Crossrefs

Programs

  • Magma
    MolienSeries(CoxeterGroup("F4")); // Sergei Haller (sergei(AT)sergei-haller.de), Dec 21 2006
    
  • Magma
    R:=PowerSeriesRing(Integers(), 70); Coefficients(R!( 1/((1-x)*(1-x^3)*(1-x^4)*(1-x^6)) )); // G. C. Greubel, Sep 08 2019
    
  • Maple
    a:= proc(n) local m, r; m := iquo (n, 12, 'r'); r:= r+1; ([4, 5, 6, 8, 10, 11, 14, 16, 18, 21, 24, 26][r]+ (6+r+4*m)*m)*m+ [1$3, 2, 3$2, 5, 6, 7, 9, 11, 12][r] end: seq(a(n), n=0..100); # Alois P. Heinz, Oct 06 2008
  • Mathematica
    Take[CoefficientList[Series[1/((1-x^2)(1-x^6)(1-x^8)(1-x^12)),{x,0,130}], x], {1,-1,2}] (* or *) LinearRecurrence[ {1,0,1,0,-1,1,-2,1,-1,0,1,0,1,-1},{1,1,1,2,3,3,5,6,7,9,11,12,16,18},70] (* Harvey P. Dale, Feb 07 2012 *)
  • PARI
    my(x='x+O('x^70)); Vec(1/((1-x)*(1-x^3)*(1-x^4)*(1-x^6))) \\ G. C. Greubel, Sep 08 2019
    
  • Sage
    def A008670_list(prec):
        P. = PowerSeriesRing(ZZ, prec)
        return P(1/((1-x)*(1-x^3)*(1-x^4)*(1-x^6))).list()
    A008670_list(70) # G. C. Greubel, Sep 08 2019

Formula

G.f.: 1/((1-x)*(1-x^3)*(1-x^4)*(1-x^6)). [Corrected by Ralf Stephan, Apr 29 2014]
a(n) = a(n-1) + a(n-3) - a(n-5) + a(n-6) - 2*a(n-7) + a(n-8) - a(n-9) + a(n-11) + a(n-13) - a(n-14), with a(0)=1, a(1)=1, a(2)=1, a(3)=2, a(4)=3, a(5)=3, a(6)=5, a(7)=6, a(8)=7, a(9)=9, a(10)=11, a(11)=12, a(12)=16, a(13)=18. - Harvey P. Dale, Feb 07 2012
a(n) ~ (1/432)*n^3. - Ralf Stephan, Apr 29 2014
a(n) = (120*floor(n/6)^3 + 60*(m+7)*floor(n/6)^2 + 2*(m^5-15*m^4+75*m^3-135*m^2+134*m+240)*floor(n/6) + 3*(m^5-15*m^4+75*m^3-135*m^2+84*m+70) + (m^5-15*m^4+75*m^3-135*m^2+44*m+30)*(-1)^floor(n/6))/240 where m = (n mod 6). - Luce ETIENNE, Aug 14 2018
a(n) = 1 + floor((2*n^3 + 42*n^2 + n*(279 + 9*(-1)^n - 48*[(n mod 3)=2]))/864) where [] is the Iverson bracket. - Hoang Xuan Thanh, Jun 22 2025

A010884 Period 5: repeat [1,2,3,4,5].

Original entry on oeis.org

1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1
Offset: 0

Views

Author

Keywords

Comments

Partial sums are given by A130483(n)+n+1. - Hieronymus Fischer, Jun 08 2007
4115/33333 = 0.12345123451234512345... - Eric Desbiaux, Nov 03 2008

Crossrefs

Cf. A177038 (decimal expansion of (195+sqrt(65029))/314).

Programs

Formula

a(n) = 1 + (n mod 5). - Paolo P. Lava, Nov 21 2006
From Hieronymus Fischer, Jun 08 2007: (Start)
G.f.: (5*x^4+4*x^3+3*x^2+2*x+1)/(1-x^5) = (5*x^6-6*x^5+1)/((1-x^5)*(1-x)^2).
a(n) = A010874(n)+1. (End)
a(n) = a(n-5). - Wesley Ivan Hurt, Jan 15 2022

A053841 (Sum of digits of n written in base 6) modulo 6.

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 0, 2, 3, 4, 5, 0, 1, 3, 4, 5, 0, 1, 2, 4, 5, 0, 1, 2, 3, 5, 0, 1, 2, 3, 4, 1, 2, 3, 4, 5, 0, 2, 3, 4, 5, 0, 1, 3, 4, 5, 0, 1, 2, 4, 5, 0, 1, 2, 3, 5, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 2, 3, 4, 5, 0, 1, 3, 4, 5, 0, 1, 2, 4, 5, 0, 1, 2, 3, 5, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 5, 1, 2, 3
Offset: 0

Views

Author

Henry Bottomley, Mar 28 2000

Keywords

Comments

a(n) is the fifth row of the array in A141803. - Andrey Zabolotskiy, May 18 2016

Crossrefs

Programs

  • Mathematica
    Mod[DigitSum[Range[0, 100], 6], 6] (* Paolo Xausa, Aug 09 2024 *)
  • PARI
    a(n) = vecsum(digits(n, 6)) % 6; \\ Michel Marcus, May 18 2016

Formula

a(n) = A010875(A053827(n)). - Andrey Zabolotskiy, May 18 2016

A080063 a(n) = n mod (spf(n)+1), where spf(n) is the smallest prime dividing n (A020639).

Original entry on oeis.org

1, 2, 3, 1, 5, 0, 7, 2, 1, 1, 11, 0, 13, 2, 3, 1, 17, 0, 19, 2, 1, 1, 23, 0, 1, 2, 3, 1, 29, 0, 31, 2, 1, 1, 5, 0, 37, 2, 3, 1, 41, 0, 43, 2, 1, 1, 47, 0, 1, 2, 3, 1, 53, 0, 1, 2, 1, 1, 59, 0, 61, 2, 3, 1, 5, 0, 67, 2, 1, 1, 71, 0, 73, 2, 3, 1, 5, 0, 79, 2, 1, 1, 83, 0, 1, 2, 3, 1, 89, 0, 3, 2, 1, 1, 5, 0
Offset: 1

Views

Author

Reinhard Zumkeller, Jan 24 2003

Keywords

Comments

a(n) = 0 iff n mod 6 = 0 (A008588);
a(n) = 2 iff n mod 6 = 2 (A016933);
for n>1: a(n)=n iff n is prime (A000040, A008578).

Crossrefs

A130910 Sum {0<=k<=n, k mod 16} (Partial sums of A130909).

Original entry on oeis.org

0, 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 120, 121, 123, 126, 130, 135, 141, 148, 156, 165, 175, 186, 198, 211, 225, 240, 240, 241, 243, 246, 250, 255, 261, 268, 276, 285, 295, 306, 318, 331, 345, 360, 360, 361, 363, 366, 370, 375, 381, 388
Offset: 0

Views

Author

Hieronymus Fischer, Jun 11 2007

Keywords

Crossrefs

Programs

  • Mathematica
    Accumulate[Mod[Range[0,60],16]] (* Harvey P. Dale, May 30 2020 *)

Formula

a(n)=120*floor(n/16)+A130909(n)*(A130909(n)+1)/2. - G.f.: g(x)=(sum{1<=k<16, k*x^k})/((1-x^16)(1-x)). Also: g(x)=x(15x^16-16x^15+1)/((1-x^16)(1-x)^3).
a(n) = +a(n-1) +a(n-16) -a(n-17). G.f. ( x*(1 +2*x +3*x^2 +4*x^3 +5*x^4 +6*x^5 +7*x^6 +8*x^7 +9*x^8 +10*x^9 +11*x^10 +12*x^11 +13*x^12 +14*x^13 +15*x^14) ) / ( (1+x) *(1+x^2) *(1+x^4) *(1+x^8) *(x-1)^2 ). - R. J. Mathar, Nov 05 2011

A306331 Numbers congruent to 6 or 31 mod 38.

Original entry on oeis.org

6, 31, 44, 69, 82, 107, 120, 145, 158, 183, 196, 221, 234, 259, 272, 297, 310, 335, 348, 373, 386, 411, 424, 449, 462, 487, 500, 525, 538, 563, 576, 601, 614, 639, 652, 677, 690, 715, 728, 753, 766, 791, 804, 829, 842, 867, 880, 905
Offset: 1

Views

Author

Davis Smith, Feb 07 2019

Keywords

Comments

A007310(a(n) + 1) is always a multiple of 19.
A020639(A007310(a(n) + 1)) = 5, 7, 11, 13, 17, or 19.
It equals 5 when n is a term in A273669.
It equals 7 when n is congruent to 3 or 12 (mod 14) but not a term in A273669.
It equals 11 when n is congruent to 4 or 19 (mod 22) but not a case where it equals 5 or 7.
It equals 13 when n is congruent to 5 or 22 (mod 26) (one more than a term in A306285) but not a case where it equals 5, 7, or 11.
It equals 17 when n is congruent to 6 or 29 (mod 34) but not a case where it equals 5, 7, 11, or 13.
For all other cases, it equals 19.
a(n) and (n - 1) have the same remainder (mod 6) (see A010875).

Crossrefs

Programs

  • Maple
    seq(seq(38*i+j, j=[6, 31]), i=0..200);
  • Mathematica
    Select[Range[200], MemberQ[{6, 31}, Mod[#, 38]] &]
    Union[38Range[30] - 32, 38Range[30] - 7] (* Alonso del Arte, Feb 08 2019 *)
  • PARI
    for(n=6, 905, if((n%38==6) || (n%38==31), print1(n, ", ")))
    
  • PARI
    Vec(x*(6 + 25*x + 7*x^2) / ((1 - x)^2*(1 + x)) + O(x^40)) \\ Colin Barker, Feb 09 2019
    
  • Scala
    (6 to 1108 by 38).union(31 to 1133 by 38).sorted // Alonso del Arte, Feb 08 2019

Formula

G.f.: x*(6 + 25*x + 7*x^2) / ((1 - x)^2*(1 + x)). - Colin Barker, Feb 09 2019
a(n) = a(n - 1) + a(n - 2) - a(n - 3) for n > 3.
a(n) = 19*n - 10 + 3*(-1)^n. - Wesley Ivan Hurt, Mar 10 2019
a(n) = 19*n - 13 when n is odd and 19*n - 7 when n is even.
a(n) = 19*n - (A040031(n + 1) + 1).
E.g.f.: 7 + (19*x - 10)*exp(x) + 3*exp(-x). - David Lovler, Sep 10 2022
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