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 1-3 of 3 results.

A264901 Sorted powers C^z = A^x + B^y with all positive integers and x,y,z > 2, with multiplicity.

Original entry on oeis.org

16, 32, 64, 64, 128, 128, 128, 243, 256, 256, 512, 512, 512, 512, 512, 512, 1024, 1024, 1024, 1024, 1024, 1024, 2048, 2048, 2048, 2744, 4096, 4096, 4096, 4096, 6561, 6561, 6561, 6561, 8192, 8192, 8192, 8192, 8192, 8192
Offset: 1

Views

Author

Anatoly E. Voevudko, Nov 28 2015

Keywords

Comments

We do not distinguish between the representations C^z = A^x + B^y and C^z = B^y + A^x.
This sequence is based on the type of equation involved in Beal's conjecture.

Examples

			128 = 64 + 64 ==> 2^7 = 2^6 + 2^6 = 2^6 + 4^3 = 4^3 + 4^3 (but not 4^3 + 2^6).
		

Crossrefs

Programs

  • PARI
    b264901(lim)=
    {my(Lc=List(1),Lb=List(),La=Lb,czn,lan,lbn,lcn,lim2=logint(lim,2),lim3);
    for(z=3,lim2,lim3=sqrtnint(lim, z); for(C=2,lim3, listput(Lc, C^z)));
    lcn=#Lc; if(lcn==0, return(-1));
    for(i=1,lcn, for(j=i,lcn, czn=Lc[i]+Lc[j]; if(czn>lim, next);
    La=findinlista(Lc,czn); lan=#La; if(!lan, next);
    for(k=1,lan, listput(Lb, czn));)); lbn=#Lb; listsort(Lb);
    for(i=1,lbn, print(i," ",Lb[i]))}
    findinlista(list, item, sind=1)=
    {my(ln=#list, Li=List()); if(ln==0 || sind<1 || sind>ln, return(Li));
    for(i=sind, ln, if(list[i]==item, listput(Li,i))); return(Li);}

A265731 Powers C^z = A^x + B^y with all positive integers and x,y,z > 1, without multiplicity.

Original entry on oeis.org

8, 9, 16, 25, 32, 36, 64, 81, 100, 125, 128, 144, 169, 196, 225, 243, 256, 289, 324, 343, 400, 441, 512, 576, 625, 676, 784, 841, 900, 1000, 1024, 1089, 1156, 1225, 1296, 1369, 1521, 1600, 1681, 1728, 1764, 1849, 2025, 2048, 2197, 2304, 2500, 2601, 2704, 2744, 2809, 2916, 3025, 3125
Offset: 1

Views

Author

Anatoly E. Voevudko, Dec 14 2015

Keywords

Comments

This type of equation is used in the Fermat-Catalan conjecture, the ABC conjecture, etc., of course, with additional restrictions and conditions.

Examples

			8 = 2^3 = 2^2 + 2^2; 9 = 3^2 = 1^3 + 2^3; 16 = 4^2 = 2^3 + 2^3; etc.
		

Crossrefs

Programs

  • PARI
    A265731(lim,bflag=0)={my(Lcz=List(1),Lb=List(),czn,lczn,lbn,lim2=logint(lim, 2),lim3);
    for(z=2, lim2, lim3=sqrtnint(lim, z); for(C=2, lim3, listput(Lcz, C^z)));
    Lcz=Set(Lcz); lczn = #Lcz; if(lczn==0,return(-1));
    for(i=1, lczn, for(j=i, lczn, czn=Lcz[i]+Lcz[j]; if(czn>lim, break);
    if(setsearch(Lcz, czn), listput(Lb, czn)))); listsort(Lb,1);  lbn=#Lb;
    if(bflag, for(i=1,lbn,print(i , " ", Lb[i]))); if(!bflag,return(Vec(Lb))); }
    \\ Anatoly E. Voevudko, Nov 23 2015

A265732 Powers C^z = A^x + B^y with all positive integers and x,y,z > 1, with multiplicity.

Original entry on oeis.org

8, 9, 16, 16, 25, 25, 32, 32, 32, 36, 36, 64, 64, 64, 81, 81, 100, 100, 100, 125, 125, 128, 128, 128, 128, 128, 128, 144, 144, 169, 196, 225, 225, 225, 225, 243, 256, 256, 256, 289, 289, 289, 324, 324, 324, 343, 400, 400, 400, 441, 512, 512, 512, 512, 512, 512, 512, 512, 512, 512, 512, 512, 512, 512, 576
Offset: 1

Views

Author

Anatoly E. Voevudko, Dec 14 2015

Keywords

Comments

We do not distinguish between the equations C^z = A^x + B^y and C^z = B^y + A^x.
This type of equation is used in the Fermat-Catalan conjecture, the ABC conjecture, etc., of course with additional restrictions and conditions.

Examples

			128 = 64 + 64 ==> 2^7 = 8^2 + 8^2 = 8^2 + 4^3 = 8^2 + 2^6 = 4^3 + 4^3 = 4^3 + 2^6 = 2^6 + 2^6 (but not 4^3 + 8^2, 2^6 + 8^2, 2^6 + 4^3).
		

Crossrefs

Programs

  • PARI
    A265732(lim,bflag=0)=
    {my(Lc=List(1),Lb=List(),La=Lb,czn,lcn,lan,lim2=logint(lim,2),lim3,k);
    for(z=2,lim2,lim3=sqrtnint(lim,z); for(C=2,lim3,listput(Lc,C^z)) );
    lcn = #Lc; if(lcn==0,return(-1));
    for(i=1,lcn, for(j=i,lcn, czn=Lc[i]+Lc[j]; if(czn>lim, next);
    La=findinlista(Lc, czn); lan=#La; if(!lan, next);
    for(k=1,lan, listput(Lb, czn)))); lcn=#Lb; listsort(Lb,0);
    if(bflag,for(i=1,lcn,print(i ," ",Lb[i]))); if(!bflag,return(Vec(Lb)));
    }
    findinlista(list, item, sind=1)={my(ln=#list, Li=List());
    if(ln==0||sind<1||sind>ln, return(Li));
    for(i=sind, ln, if(list[i]==item, listput(Li,i))); return(Li);
    } \\ Anatoly E. Voevudko, Nov 23 2015
Showing 1-3 of 3 results.