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.

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A115665 Brilliant numbers (A078972) whose digit reversal is a semiprime (A001358).

Original entry on oeis.org

4, 6, 9, 15, 49, 121, 143, 169, 187, 221, 289, 319, 323, 341, 437, 493, 533, 551, 559, 589, 629, 667, 737, 767, 781, 817, 851, 871, 893, 899, 913, 923, 949, 961, 979, 989, 1027, 1067, 1079, 1121, 1219, 1247, 1273, 1343, 1357, 1387, 1411, 1513, 1577
Offset: 1

Views

Author

Giovanni Resta, Jan 31 2006

Keywords

Examples

			551=19*29 is brilliant and 155=5*31 is semiprime.

Crossrefs

Cf. A001358, A078972, A115666.

A115666 Semiprimes (A001358) whose digit reversal is a brilliant number (A078972).

Original entry on oeis.org

4, 6, 9, 51, 94, 121, 122, 143, 155, 158, 169, 178, 187, 319, 323, 329, 335, 341, 394, 398, 718, 734, 737, 766, 767, 781, 913, 926, 949, 955, 961, 979, 982, 985, 989, 998, 1141, 1202, 1211, 1273, 1322, 1343, 1405, 1415, 1655, 1691, 1703, 1714, 1807
Offset: 1

Views

Author

Giovanni Resta, Jan 31 2006

Keywords

Examples

			155=5*31 is semiprime and 551=19*29 is brilliant.

Crossrefs

Cf. A001358, A078972, A115665.

A115674 Cubes whose digit reversal is a brilliant number (A078972).

Original entry on oeis.org

12167, 79507, 175616, 195112, 941192, 1092727, 12167000, 71473375, 79507000, 175616000, 177504328, 195112000, 318611987, 331373888, 338608873, 941192000, 1092727000, 1865409391, 3010936384, 7088952961, 11405819251
Offset: 1

Views

Author

Giovanni Resta, Jan 31 2006

Keywords

Examples

			12167=23^3 and 76121=163*467 is brilliant.

Crossrefs

Cf. A078972, A115673.

A115677 Brilliant numbers (A078972) whose digit reversal is a triangular number.

Original entry on oeis.org

6, 10, 649, 1207, 54253, 56341, 60391, 66259, 66331, 101971, 155143, 166339, 351433, 672319, 3003193, 3054853, 5043763, 5631229, 5858119, 6163831, 6256603, 6462847, 6473899, 6556177, 6687883, 8210989, 8236513, 8735491, 8788033, 10716571, 11576143
Offset: 1

Views

Author

Giovanni Resta, Jan 31 2006

Keywords

Examples

			649=11*59 is brilliant and 946=T(43).

Crossrefs

Cf. A078972, A115678.

Programs

  • Mathematica
    bnoQ[n_]:=Module[{fi=FactorInteger[n],tfi,nn}, tfi=Transpose[fi]; Total[tfi[[2]]]==2 &&IntegerLength[First[tfi[[1]]]] == IntegerLength[Last[tfi[[1]]]]]; tnoQ[n_]:=IntegerQ[(Sqrt[1 +8FromDigits[ Reverse[IntegerDigits[n]]]]-1)/2]; Select[Select[Range[700000], bnoQ], tnoQ]  (* Harvey P. Dale, Apr 17 2011 *)

Extensions

a(15)-a(31) from Donovan Johnson, Apr 26 2011

A115679 Brilliant numbers (A078972) whose digit reversal is a pentagonal number (A000326).

Original entry on oeis.org

10, 15, 21, 517, 529, 671, 1513, 6241, 15251, 23129, 27161, 53297, 59701, 79091, 104977, 299911, 559411, 575051, 597557, 1560101, 2178727, 2273641, 2390393, 2966429, 5354893, 5429329, 5435761, 5613197, 5664721, 5988449, 6218521
Offset: 1

Views

Author

Giovanni Resta, Jan 31 2006

Keywords

Examples

			1513=17*89 is brilliant and 3151 is the 46th pentagonal number.

Crossrefs

Cf. A000326, A078972, A115680.

A115680 Pentagonal numbers (A000326) whose digit reversal is a brilliant number (A078972).

Original entry on oeis.org

12, 51, 176, 715, 925, 1426, 3151, 3290, 10795, 15251, 16172, 19097, 79235, 92132, 114955, 117460, 119992, 127750, 150575, 355510, 755795, 779401, 1010651, 1108970, 1258126, 1274665, 1294097, 1463722, 1466687, 1675345, 1881040
Offset: 1

Views

Author

Giovanni Resta, Jan 31 2006

Keywords

Examples

			3151 is the 46th pentagonal number and 1513=17*89 is brilliant.

Crossrefs

Cf. A000326, A078972, A115679.

A115912 Numbers k such that k + prime(k) is a brilliant number (A078972).

Original entry on oeis.org

12, 30, 36, 56, 60, 84, 86, 120, 140, 156, 174, 182, 198, 210, 212, 216, 230, 232, 276, 320, 340, 398, 428, 478, 486, 512, 536, 606, 680, 708, 756, 810, 1170, 1210, 1444, 1498, 1522, 1624, 1696, 1800, 1852, 1900, 2014, 2100, 2190, 2300, 2364, 2422
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			1444 + prime(1444) = 103*131.

Crossrefs

Cf. A078972, A115913.

A115913 Numbers k such that prime(k) - k is a brilliant number (A078972).

Original entry on oeis.org

5, 7, 9, 12, 52, 60, 64, 74, 78, 96, 118, 122, 124, 132, 138, 150, 160, 166, 184, 186, 190, 210, 234, 240, 250, 252, 256, 258, 284, 306, 314, 334, 438, 462, 500, 570, 612, 666, 678, 690, 874, 1056, 1396, 1650, 1784, 1860, 1946, 1994, 2020, 2052, 2188
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			prime(666) - 666 = 59*73.

Crossrefs

Cf. A078972, A115912.

A115914 Numbers k such that k + sigma(k) is a brilliant number (A078972).

Original entry on oeis.org

7, 17, 50, 71, 93, 117, 149, 187, 201, 217, 221, 247, 256, 263, 265, 327, 329, 371, 381, 383, 385, 389, 392, 401, 403, 413, 427, 449, 461, 485, 497, 503, 515, 525, 533, 543, 569, 605, 623, 635, 649, 667, 685, 701, 723, 763, 803, 821, 831, 835, 837, 839
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			sigma(117) + 117 = 299 = 13*23.

Crossrefs

Cf. A078972, A115916.

A115915 Numbers k such that k + phi(k) is a brilliant number (A078972).

Original entry on oeis.org

4, 5, 9, 10, 11, 13, 61, 87, 127, 181, 241, 253, 265, 287, 295, 321, 323, 349, 361, 363, 377, 397, 407, 409, 421, 451, 457, 473, 481, 485, 511, 515, 527, 537, 541, 581, 595, 631, 635, 671, 695, 705, 721, 731, 751, 757, 763, 769, 793, 805, 807, 843, 851, 867
Offset: 1

Views

Author

Giovanni Resta, Feb 06 2006

Keywords

Examples

			295 + phi(295) = 527 = 17*31.

Crossrefs

Cf. A078972, A115916.
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