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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A291361 The arithmetic function u(n,2,6).

Original entry on oeis.org

7, 2, 3, 2, 5, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3, 2, 7, 2, 5, 2, 3, 2, 7, 2, 7, 2, 3, 2, 5, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3, 2, 7, 2, 5, 2, 3, 2, 7, 2, 7, 2, 3, 2, 5, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3, 2, 7, 2, 5, 2, 3, 2, 7, 2, 7, 2, 3, 2, 5, 2, 7, 2, 3, 2, 7, 2, 7, 2, 3
Offset: 1

Views

Author

Robert Price, Aug 23 2017

Keywords

Crossrefs

Programs

  • Mathematica
    u[n_, m_, h_] := (d = Divisors[n]; Min[(h*Ceiling[m/d] - h + 1)*d]); Table[u[n, 2, 6], {n, 1, 70}]
  • PARI
    A291361(n, m=2, h=6) = { my(p=0,k); fordiv(n,d,k = d*(h*ceil(m/d) - h + 1); if(!p || (k < p), p = k)); (p); }; \\ Antti Karttunen, Oct 01 2018

Extensions

More terms from Antti Karttunen, Oct 01 2018

A291362 The arithmetic function u(n,2,7).

Original entry on oeis.org

8, 2, 3, 2, 5, 2, 7, 2, 3, 2, 8, 2, 8, 2, 3, 2, 8, 2, 8, 2, 3, 2, 8, 2, 5, 2, 3, 2, 8, 2, 8, 2, 3, 2, 5, 2, 8, 2, 3, 2, 8, 2, 8, 2, 3, 2, 8, 2, 7, 2, 3, 2, 8, 2, 5, 2, 3, 2, 8, 2, 8, 2, 3, 2, 5, 2, 8, 2, 3, 2, 8, 2, 8, 2, 3, 2, 7, 2, 8, 2, 3, 2, 8, 2, 5, 2, 3, 2, 8, 2, 7, 2, 3, 2, 5, 2, 8, 2, 3, 2, 8, 2, 8, 2, 3
Offset: 1

Views

Author

Robert Price, Aug 23 2017

Keywords

Crossrefs

Programs

  • Mathematica
    u[n_, m_, h_] := (d = Divisors[n]; Min[(h*Ceiling[m/d] - h + 1)*d]); Table[u[n, 2, 7], {n, 1, 70}]
  • PARI
    A291362(n, m=2, h=7) = { my(p=0,k); fordiv(n,d,k = d*(h*ceil(m/d) - h + 1); if(!p || (k < p), p = k)); (p); }; \\ Antti Karttunen, Oct 01 2018

Extensions

More terms from Antti Karttunen, Oct 01 2018

A291363 The arithmetic function u(n,2,8).

Original entry on oeis.org

9, 2, 3, 2, 5, 2, 7, 2, 3, 2, 9, 2, 9, 2, 3, 2, 9, 2, 9, 2, 3, 2, 9, 2, 5, 2, 3, 2, 9, 2, 9, 2, 3, 2, 5, 2, 9, 2, 3, 2, 9, 2, 9, 2, 3, 2, 9, 2, 7, 2, 3, 2, 9, 2, 5, 2, 3, 2, 9, 2, 9, 2, 3, 2, 5, 2, 9, 2, 3, 2, 9, 2, 9, 2, 3, 2, 7, 2, 9, 2, 3, 2, 9, 2, 5, 2, 3, 2, 9, 2, 7, 2, 3, 2, 5, 2, 9, 2, 3, 2, 9, 2, 9, 2, 3
Offset: 1

Views

Author

Robert Price, Aug 23 2017

Keywords

Crossrefs

Programs

  • Mathematica
    u[n_, m_, h_] := (d = Divisors[n]; Min[(h*Ceiling[m/d] - h + 1)*d]); Table[u[n, 2, 8], {n, 1, 70}]
  • PARI
    A291363(n, m=2, h=8) = { my(p=0,k); fordiv(n,d,k = d*(h*ceil(m/d) - h + 1); if(!p || (k < p), p = k)); (p); }; \\ Antti Karttunen, Oct 01 2018

Extensions

More terms from Antti Karttunen, Oct 01 2018

A291514 The arithmetic function uhat(n,3,5).

Original entry on oeis.org

-9, -9, -9, -9, -9, -9, -9, -9, -9, -10, -11, -12, -13, -14, -15, -16, -17, -18, -19, -20, -21, -22, -23, -24, -25, -26, -27, -28, -29, -30, -31, -32, -33, -34, -35, -36, -37, -38, -39, -40, -41, -42, -43, -44, -45, -46, -47, -48, -49, -50, -51, -52, -53, -54, -55, -56, -57, -58, -59, -60, -61, -62, -63, -64, -65, -66, -67, -68, -69, -70
Offset: 1

Views

Author

Robert Price, Aug 25 2017

Keywords

Crossrefs

Programs

  • Mathematica
    delta[r_, k_, d_] := If[r < k, (k - r)*r - (d - 1), If[k < r && r < d, (d - r)*(r - k) - (d - 1), If[k == r && r == d, d - 1, 0]]] uhat[n_, m_, h_] := (dx = Divisors[n]; dmin = n; For[i = 1, i ≤ Length[dx], i++, d = dx[[i]]; k = m - d*Ceiling[m/d] + d; r = h - d*Ceiling[h/d] + d; If[h ≤ Min[k, d - 1], dmin = Min[dmin, n, (h*Ceiling[m/d] - h + 1)*d, h*m - h*h + 1], dmin = Min[dmin, n, h*m - h*h + 1 - delta[r, k, d]]]]; dmin) Table[uhat[n, 3, 5], {n, 1, 70}]

Formula

Conjectures from Chai Wah Wu, Jun 10 2025: (Start)
a(n) = 2*a(n-1) - a(n-2) for n > 10.
G.f.: x*(-x^9 + 9*x - 9)/(x - 1)^2. (End)

A291520 The arithmetic function uhat(n,4,2).

Original entry on oeis.org

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

Views

Author

Robert Price, Aug 25 2017

Keywords

Crossrefs

Programs

  • Mathematica
    delta[r_, k_, d_] := If[r < k, (k - r)*r - (d - 1), If[k < r && r < d, (d - r)*(r - k) - (d - 1), If[k == r && r == d, d - 1, 0]]] uhat[n_, m_, h_] := (dx = Divisors[n]; dmin = n; For[i = 1, i ≤ Length[dx], i++, d = dx[[i]]; k = m - d*Ceiling[m/d] + d; r = h - d*Ceiling[h/d] + d; If[h ≤ Min[k, d - 1], dmin = Min[dmin, n, (h*Ceiling[m/d] - h + 1)*d, h*m - h*h + 1], dmin = Min[dmin, n, h*m - h*h + 1 - delta[r, k, d]]]]; dmin) Table[uhat[n, 4, 2], {n, 1, 70}]

Formula

Conjectures from Chai Wah Wu, Jun 10 2025: (Start)
a(n) = a(n-2) for n > 5.
G.f.: x*(-2*x^4 - 2*x^3 - 2*x^2 - 2*x - 1)/(x^2 - 1). (End)

A289186 The arithmetic function v_4(n,5).

Original entry on oeis.org

0, 1, 0, 1, 2, 2, 1, 3, 2, 2, 4, 3, 4, 5, 3, 4, 6, 4, 4, 7, 4, 5, 8, 5, 6, 9, 8, 6, 10, 6, 6, 11, 8, 10, 12, 8, 8, 13, 8, 8, 14, 9, 8, 15, 10, 10, 16, 14, 10, 17, 12, 11, 18, 11, 16, 19, 12, 12, 20, 12, 12, 21, 12, 15, 22, 14, 16, 23, 20
Offset: 2

Views

Author

Robert Price, Aug 16 2017

Keywords

References

  • J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008).

Crossrefs

Programs

  • Mathematica
    v[g_, n_, h_] := (d = Divisors[n]; Max[(Floor[(d - 1 - GCD[d, g])/h] + 1)*n/d]); Table[v[4, n, 5], {n, 2, 70}]
    a[n_]:=n*Max[Table[(Floor[(d - 1 - GCD[d, 4])/5] + 1)/d, {d, Divisors[n]}]]; Table[a[n], {n, 2, 100}] (* Vincenzo Librandi, Aug 17 2017 *)

A290978 The arithmetic function v_2(n,5).

Original entry on oeis.org

0, 1, 1, 1, 2, 2, 2, 3, 2, 2, 4, 3, 4, 5, 4, 4, 6, 4, 5, 7, 4, 5, 8, 5, 6, 9, 8, 6, 10, 6, 8, 11, 8, 10, 12, 8, 8, 13, 10, 8, 14, 9, 11, 15, 10, 10, 16, 14, 10, 17, 13, 11, 18, 11, 16, 19, 12, 12, 20, 12, 12, 21, 16, 15, 22, 14, 17, 23, 20
Offset: 2

Views

Author

Robert Price, Aug 16 2017

Keywords

References

  • J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008).

Crossrefs

Programs

  • Mathematica
    v[g_, n_, h_] := (d = Divisors[n]; Max[(Floor[(d - 1 - GCD[d, g])/h] + 1)*n/d]); Table[v[2, n, 5], {n, 2, 70}]
    a[n_]:=n Max[Table[(Floor[(d - 1 - GCD[d, 2])/5] + 1)/d, {d, Divisors[n]}]]; Table[a[n], {n, 2, 100}] (* Vincenzo Librandi, Aug 17 2017 *)

A290979 The arithmetic function v_2(n,6).

Original entry on oeis.org

0, 1, 1, 1, 2, 1, 2, 3, 2, 2, 4, 2, 2, 5, 4, 3, 6, 3, 5, 7, 4, 4, 8, 5, 4, 9, 7, 5, 10, 5, 8, 11, 6, 7, 12, 6, 6, 13, 10, 7, 14, 7, 11, 15, 8, 8, 16, 8, 10, 17, 13, 9, 18, 11, 14, 19, 10, 10, 20, 10, 10, 21, 16, 13, 22, 11, 17, 23, 14, 12, 24, 12, 12, 25, 19, 14, 26
Offset: 2

Views

Author

Robert Price, Aug 16 2017

Keywords

References

  • J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008).

Crossrefs

Programs

  • Mathematica
    v[g_, n_, h_] := (d = Divisors[n]; Max[(Floor[(d - 1 - GCD[d, g])/h] + 1)*n/d]); Table[v[2, n, 6], {n, 2, 70}]
    a[n_]:=n Max[Table[(Floor[(d - 1 - GCD[d, 2])/6] + 1)/d, {d, Divisors[n]}]]; Table[a[n], {n, 2, 100}] (* Vincenzo Librandi, Aug 19 2017 *)

A290981 The arithmetic function v_4(n,6).

Original entry on oeis.org

0, 1, 0, 1, 2, 1, 1, 3, 2, 2, 4, 2, 2, 5, 2, 3, 6, 3, 4, 7, 4, 4, 8, 5, 4, 9, 4, 5, 10, 5, 5, 11, 6, 7, 12, 6, 6, 13, 8, 7, 14, 7, 8, 15, 8, 8, 16, 8, 10, 17, 8, 9, 18, 11, 9, 19, 10, 10, 20, 10, 10, 21, 10, 13, 22, 11, 12, 23, 14
Offset: 2

Views

Author

Robert Price, Aug 16 2017

Keywords

References

  • J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008).

Crossrefs

Programs

  • Mathematica
    v[g_, n_, h_] := (d = Divisors[n]; Max[(Floor[(d - 1 - GCD[d, g])/h] + 1)*n/d]); Table[v[4, n, 6], {n, 2, 70}]
    a[n_]:=n Max[Table[(Floor[(d - 1 - GCD[d, 4])/6] + 1)/d, {d, Divisors[n]}]]; Table[a[n], {n, 2, 100}] (* Vincenzo Librandi, Aug 19 2017 *)

A290982 The arithmetic function v_5(n,6).

Original entry on oeis.org

1, 1, 2, 0, 3, 1, 4, 3, 5, 2, 6, 2, 7, 5, 8, 3, 9, 3, 10, 7, 11, 4, 12, 4, 13, 9, 14, 5, 15, 5, 16, 11, 17, 5, 18, 6, 19, 13, 20, 7, 21, 7, 22, 15, 23, 8, 24, 8, 25, 17, 26, 9, 27, 10, 28, 19, 29, 10, 30, 10, 31, 21, 32, 10, 33, 11, 34, 23, 35
Offset: 2

Views

Author

Robert Price, Aug 16 2017

Keywords

References

  • J. Butterworth, Examining the arithmetic function v_g(n,h). Research Papers in Mathematics, B. Bajnok, ed., Gettysburg College, Vol. 8 (2008).

Crossrefs

Programs

  • Mathematica
    v[g_, n_, h_] := (d = Divisors[n]; Max[(Floor[(d - 1 - GCD[d, g])/h] + 1)*n/d]); Table[v[5, n, 6], {n, 2, 70}]
    a[n_]:=n Max[Table[(Floor[(d - 1 - GCD[d, 5])/6] + 1)/d, {d, Divisors[n]}]]; Table[a[n], {n, 2, 100}] (* Vincenzo Librandi, Aug 19 2017 *)
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