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.

A161928 Prime numbers that are not the absolute difference between a cube and a square.

Original entry on oeis.org

29, 59, 103, 137, 149, 157, 173, 179, 181, 211, 227, 263, 311, 317, 331, 349, 367, 383, 397, 419, 421, 461, 467, 479, 491, 509, 523, 541, 569, 571, 601, 607, 613, 619, 641, 643, 653, 661, 691, 709, 751, 761, 773, 787, 809, 821, 823, 839, 853, 877, 881, 883
Offset: 1

Views

Author

T. D. Noe, Jun 22 2009

Keywords

Comments

That is, for each n, there are no integers x and y such n = y^3 - x^2 or n = x^2 - y^3.

Crossrefs

These are the primes in sequence A110223. Complement of A161929.

A161929 Prime numbers that are the absolute difference between a cube and a square.

Original entry on oeis.org

2, 3, 5, 7, 11, 13, 17, 19, 23, 31, 37, 41, 43, 47, 53, 61, 67, 71, 73, 79, 83, 89, 97, 101, 107, 109, 113, 127, 131, 139, 151, 163, 167, 191, 193, 197, 199, 223, 229, 233, 239, 241, 251, 257, 269, 271, 277, 281, 283, 293, 307, 313, 337, 347, 353, 359, 373, 379
Offset: 1

Views

Author

T. D. Noe, Jun 22 2009

Keywords

Comments

That is, for each n, there are integers x and y such that n = y^3 - x^2 or n = x^2 - y^3. These are the primes not in sequence A110223. Complement of A161928.

Crossrefs

Cf. A110223, A161928.

A110222 Palindromic numbers which are not the absolute difference of a cube and a square.

Original entry on oeis.org

6, 66, 77, 88, 111, 181, 202, 363, 383, 434, 454, 474, 494, 555, 565, 595, 606, 646, 666, 707, 717, 747, 787, 818, 838, 858, 929, 949, 959, 979, 989, 1221, 1551, 1661, 2002, 2442, 2662, 3003, 3443, 3773, 3883, 4114, 4334, 4444, 4774, 4884, 5005, 5115, 5335
Offset: 1

Views

Author

Robert G. Wilson v, Jul 16 2005

Keywords

Comments

The palindromes in A110223.

Crossrefs

Cf. A109879, A074981, A110223.

Programs

  • Mathematica
    NextPalindrome[n_] := Block[ {l = Floor[ Log[10, n] + 1], idn = IntegerDigits[n]}, If[ Union[ idn] == {9}, Return[n + 2], If[l < 2, Return[n + 1], If[ FromDigits[ Reverse[ Take[ idn, Ceiling[l/2]]]] > FromDigits[ Take[ idn, -Ceiling[l/2]]], FromDigits[ Join[ Take[ idn, Ceiling[l/2]], Reverse[ Take[ idn, Floor[l/2]]]]], idfhn = FromDigits[ Take[ idn, Ceiling[l/2]]] + 1; idp = FromDigits[ Join[ IntegerDigits[ idfhn], Drop[ Reverse[ IntegerDigits[ idfhn]], Mod[l, 2]]]]]]]]; t1 = NestList[ NextPalindrome, 0, 130]; t2 = Union[ Flatten[ Table[ Select[ Table[ Abs[n^3 - m^2], {m, 0, 10000}], # < 10^3 &], {n, -5000, 5000}]]]; Take[ Complement[t1, Intersection[t1, t2]], 50]
Showing 1-3 of 3 results.

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

Content is available under The OEIS End-User License Agreement.