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 1-10 of 12 results. Next

A162817 Positive numbers n such that 40*n/(40+n) are integers.

Original entry on oeis.org

10, 24, 40, 60, 120, 160, 280, 360, 760, 1560
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694
Cf. A127730. [From Franklin T. Adams-Watters, Aug 07 2009]

Programs

  • Mathematica
    f[a_,b_]:=(a*b)/(a+b); a=40;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Select[Range[1600],IntegerQ[(40#)/(40+#)]&] (* Harvey P. Dale, Oct 11 2011 *)

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162818 Strictly positive numbers n such that (42*n)/(42+n) is an integer.

Original entry on oeis.org

7, 21, 42, 56, 84, 105, 154, 210, 252, 399, 546, 840, 1722
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817
Cf. A127730 - Franklin T. Adams-Watters, Aug 07 2009

Programs

  • Mathematica
    f[a_,b_]:=(a*b)/(a+b); a=42;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]],AppendTo[lst,n]],{n,9!}];lst
Select[Range[2000], Divisible[42 #, 42 + #] &] (* Harvey P. Dale, May 09 2012 *)

Extensions

Keywords fini and full added by Franklin T. Adams-Watters, Aug 07 2009

A162819 Positive numbers n such that 48*n/(48+n) are integers.

Original entry on oeis.org

16, 24, 48, 80, 96, 144, 208, 240, 336, 528, 720, 1104, 2256
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818
Cf. A127730. [From Franklin T. Adams-Watters, Aug 07 2009]

Programs

  • Mathematica
    f[a_,b_]:=(a*b)/(a+b); a=48;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Select[Range[2300],IntegerQ[(48#)/(48+#)]&] (* Harvey P. Dale, Dec 18 2018 *)

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162820 Positive numbers n such that 60*n/(60+n) are integers.

Original entry on oeis.org

12, 15, 20, 30, 40, 60, 84, 90, 120, 140, 165, 180, 240, 300, 340, 390, 540, 660, 840, 1140, 1740, 3540
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819
Cf. A127730. [From Franklin T. Adams-Watters, Aug 07 2009]

Programs

  • Mathematica
    f[a_,b_]:=(a*b)/(a+b); a=60;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162821 Positive numbers k such that 30*k/(30-k) are integers.

Original entry on oeis.org

5, 10, 12, 15, 18, 20, 21, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 39, 40, 42, 45, 48, 50, 55, 60, 66, 75, 80, 90, 105, 120, 130, 180, 210, 255, 330, 480, 930
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Comments

The number k=30 is explicitly included, treating the result of division through zero as an integer.
Row 30 of A191973.

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A191973.

Programs

  • Maple
    for m from 1 to 930 do if(m=30 or m*30 mod (m-30) = 0)then printf("%d, ", m): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    f[a_,b_]:=(a*b)/(a-b); a=30;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162822 Positive numbers k such that 36*k/(36-k) are integers.

Original entry on oeis.org

9, 12, 18, 20, 24, 27, 28, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42, 44, 45, 48, 52, 54, 60, 63, 72, 84, 90, 108, 117, 144, 180, 198, 252, 360, 468, 684, 1332
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Comments

The number k=36 is explicitly included, treating the result of division through zero as an integer.
Row 36 of A191973.

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A191973.

Programs

  • Maple
    for m from 1 to 1332 do if(m=36 or m*36 mod (m-36) = 0)then printf("%d, ", m): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    f[a_,b_]:=(a*b)/(a-b); a=36;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Sort[Join[{36},Select[Range[1500],IntegerQ[(36#)/(36-#)]&]]]  (* Harvey P. Dale, Mar 23 2011 *)

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162823 Positive numbers k such that 42*k/(42-k) are integers.

Original entry on oeis.org

6, 14, 21, 24, 28, 30, 33, 35, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 48, 49, 51, 54, 56, 60, 63, 70, 78, 84, 91, 105, 126, 140, 168, 189, 238, 294, 336, 483, 630, 924, 1806
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Comments

The number k=42 is explicitly included, treating the result of division through zero as an integer.
Row 42 of A191973.

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A162822, A191973.

Programs

  • Maple
    for m from 1 to 1806 do if(m=42 or m*42 mod (m-42) = 0)then printf("%d, ", m): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    f[a_,b_]:=(a*b)/(a-b); a=42;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Join[{42},Select[Range[2000],IntegerQ[(42#)/(42-#)]&]]//Quiet//Sort (* Harvey P. Dale, Mar 14 2020 *)

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162824 Positive numbers k such that 48*k/(48-k) are integers.

Original entry on oeis.org

12, 16, 24, 30, 32, 36, 39, 40, 42, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 56, 57, 60, 64, 66, 72, 80, 84, 96, 112, 120, 144, 176, 192, 240, 304, 336, 432, 624, 816, 1200, 2352
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Comments

The number k=48 is explicitly included.
Row 48 of A191973.

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A162822, A162823, A191973.

Programs

  • Maple
    for m from 1 to 2352 do if(m=48 or m*48 mod (m-48) = 0)then printf("%d, ", m): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    f[a_,b_]:=(a*b)/(a-b); a=48;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst

Extensions

Keywords fini,full added by R. J. Mathar, Jul 31 2009

A162825 Positive numbers k such that 60*k/(60-k) are integers.

Original entry on oeis.org

10, 12, 15, 20, 24, 30, 35, 36, 40, 42, 44, 45, 48, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 68, 69, 70, 72, 75, 76, 78, 80, 84, 85, 90, 96, 100, 105, 108, 110, 120, 132, 135, 140, 150, 160, 180, 204, 210, 240, 260, 285, 300, 360, 420
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Comments

The number k=60 is explicitly included. The last entry in the sequence is a(68) = 3660.
Row 60 of A191973.

Links

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A162822, A162823, A162824, A191973.

Programs

  • Maple
    for n from 1 to 3660 do if(n=60 or type(60*n/(60-n),integer))then printf("%d, ",n): fi: od: # Nathaniel Johnston, Jun 22 2011
  • Mathematica
    f[a_,b_]:=(a*b)/(a-b); a=60;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Select[Range[500],If[#==60,True,IntegerQ[(60#)/(60-#)]]&] (* Harvey P. Dale, Sep 26 2023 *)

Extensions

Keyword fini added by R. J. Mathar, Jul 31 2009

A162826 Positive numbers n such that 2*60*n/(60+n) are integers.

Original entry on oeis.org

12, 15, 20, 30, 36, 40, 60, 84, 90, 100, 120, 140, 165, 180, 228, 240, 300, 340, 390, 420, 540, 660, 740, 840, 1140, 1380, 1740, 2340, 3540, 7140
Offset: 1

Views

Author

Vladimir Joseph Stephan Orlovsky, Jul 13 2009

Keywords

Crossrefs

Cf. A162688, A162689, A162690, A162691, A162692, A162693, A162694, A162817, A162818, A162819, A162820, A162821, A162822, A162823, A162824, A162825

Programs

  • Mathematica
    f[a_,b_]:=(a*b)/(a+b)*2; a=60;lst={};Do[If[f[a,n]==IntegerPart[f[a,n]], AppendTo[lst,n]],{n,9!}];lst
Select[Range[8000],IntegerQ[(120#)/(60+#)]&] (* Harvey P. Dale, Mar 19 2019 *)

Extensions

Sign in definition flipped by R. J. Mathar, Jul 31 2009
Showing 1-10 of 12 results. Next

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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