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.

A372296 Taxicab numbers that are sandwiched between nonsquarefree numbers.

Original entry on oeis.org

20683, 216125, 327763, 593047, 684019, 842751, 1845649, 2691451, 4505949, 4744376, 5004125, 5772403, 6058747, 7640128, 8029000, 8216000, 8494577, 10702783, 10765603, 10821896, 11859211, 12533824, 13731319, 14916727, 16776487, 18406603, 18617625, 20616463, 22031576, 24480125, 25937576, 27529073
Offset: 1

Views

Author

Massimo Kofler, Apr 25 2024

Keywords

Examples

			20683 = 13 * 37 * 43 (between 20682 = 2 * 3^3 * 383 and 20684 = 2^2 * 5171).
216125 = 5^3 * 7 * 13 * 19 (between 216124 = 2^2 * 71 * 761 and 216126 = 2 * 3^2 * 12007).
327763 = 31 * 97 * 109 (between 327762 = 2 * 3^2 * 131 * 139 and 327764 = 2^2 * 67 * 1223).

Links

  • Christian Boyer, Les nombres Taxicabs, in Dossier Pour La Science, pp. 26-28, Volume 59 (Jeux math') April/June 2008 Paris.

Crossrefs

Cf. A001235, A011541, A013929, A371602.

Programs

  • Mathematica
    Select[Import["https://oeis.org/A001235/b001235.txt", "Table"][[;; , 2]], # < 3*10^7 && Nor @@ SquareFreeQ /@ (# + {-1, 1}) &] (* Amiram Eldar, Apr 25 2024 *)

A372848 Taxicab numbers that are sandwiched between semiprimes.

Original entry on oeis.org

4104, 171288, 1728216, 2864288, 2987712, 2991816, 3512808, 3551112, 9016488, 10424232, 12753160, 13825728, 14197248, 36047592, 43450344, 43699392, 49844032, 63057960, 72131904, 75550088, 85188096, 92384712, 107872128, 107919000, 110808000, 117258678, 119824488, 132678000
Offset: 1

Views

Author

Massimo Kofler, May 16 2024

Keywords

Comments

All terms are even numbers.

Examples

			4104 = 2^3 * 3^3 * 19 (between 4103 = 11 * 373 and 4105 = 5 * 821).
171288 = 2^3 * 3^3 * 13 * 61 (between 171287 = 157 * 1091 and 171289 = 103 * 1663).
1728216 = 2^3 * 3^5 * 7 * 127 (between 1728215 = 5 * 345643 and 1728217 = 617 * 2801).

Crossrefs

Cf. A001235, A001358.
Subsequence of A371602.

Programs

  • Mathematica
    Select[Import["https://oeis.org/A001235/b001235.txt", "Table"][[;; , 2]], # < 1.5*10^8 && PrimeOmega[# + {-1, 1}] == {2, 2} &] (* Amiram Eldar, May 16 2024 *)
Showing 1-2 of 2 results.

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

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