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 1-2 of 2 results.

A152043 Numbers expressible as the difference of two nonnegative cubes.

Original entry on oeis.org

0, 1, 7, 8, 19, 26, 27, 37, 56, 61, 63, 64, 91, 98, 117, 124, 125, 127, 152, 169, 189, 208, 215, 216, 217, 218, 271, 279, 296, 316, 331, 335, 342, 343, 386, 387, 397, 448, 469, 485, 488, 504, 511, 512, 513, 547, 602, 604, 631, 657, 665, 702, 721, 728, 729, 784
Offset: 1

Views

Author

Mark Taggart (mt2612f(AT)aol.com), Nov 21 2008

Keywords

Comments

Subsequence of A045980. - R. J. Mathar, Nov 28 2008
Contains A000578 as a subsequence. - Chandler

Examples

			E.g. 7=2^3-1^3, 8=2^3-0^3, 296=8^3-6^3.

Links

Crossrefs

Cf. A042965, A152044, A152045.
The Index to the OEIS lists many related sequences under "difference of two cubes". - N. J. A. Sloane, Dec 04 2008

Programs

  • PARI
    T=thueinit('z^3+1);
is(n)=n==0 || #select(v->v[1]<=0&&v[2]>=0, thue(T, n))>0 \\ Charles R Greathouse IV, Nov 29 2014

Extensions

Extended by Ray Chandler, Dec 04 2008

A152044 Numbers expressible as the difference of two nonnegative fourth powers.

Original entry on oeis.org

0, 1, 15, 16, 65, 80, 81, 175, 240, 255, 256, 369, 544, 609, 624, 625, 671, 1040, 1105, 1215, 1280, 1295, 1296, 1695, 1776, 2145, 2320, 2385, 2400, 2401, 2465, 2800, 3439, 3471, 3840, 4015, 4080, 4095, 4096, 4160, 4641, 5265, 5904, 5936, 6095, 6305, 6480
Offset: 1

Views

Author

Mark Taggart (mt2612f(AT)aol.com), Nov 21 2008

Keywords

Comments

This sequence seems to grow quadratically. Does a(n) ~ k*n^2 for some k? - Charles R Greathouse IV, Jan 16 2025

Examples

			E.g. 15=2^4-1^4, 175=4^4-3^4

Links

Crossrefs

Contains A000583 and A147857 as subsequences. - Chandler
Cf. A042965, A152043, A152045.

Programs

  • Mathematica
    Select[Abs[Differences/@Tuples[Range[0,12]^4,2]]//Flatten//Union,#<= 6500&] (* Harvey P. Dale, Sep 14 2020 *)
  • PARI
    is(n)=if(n<1,return(!n)); for(m=sqrtnint(n-1,4)+1, sqrtnint(n\4,3)+1, if(ispower(m^4-n,4),return(1))); 0 \\ Charles R Greathouse IV, Sep 04 2013
  • PARI
    lst(lim)=my(v=List([0]),t); lim\=1; for(n=1,sqrtnint(lim\4,3)+1, for(m=sqrtnint(max(n^4-lim,0),4), n-1, t=n^4-m^4; if(t<=lim, listput(v,t)))); vecsort(Vec(v),,8) \\ Charles R Greathouse IV, Sep 04 2013

Extensions

Extended by Ray Chandler, Dec 04 2008
Definition corrected by Harvey P. Dale, Jan 19 2018
Showing 1-2 of 2 results.

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

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