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.

A153660 Pairs of terms of A038512 which differ by 2.

Original entry on oeis.org

527, 529, 899, 901, 1079, 1081, 1157, 1159, 1271, 1273, 1649, 1651, 1679, 1681, 1817, 1819, 1919, 1921, 1961, 1963, 2117, 2119, 2171, 2173, 2327, 2329, 2489, 2491, 2507, 2509, 2771, 2773, 2867, 2869, 2921, 2923, 3131, 3133, 3149, 3151, 3401, 3403, 3587, 3589
Offset: 1

Views

Author

Howard Berman (howard_berman(AT)hotmail.com), Dec 30 2008

Keywords

Comments

In each pair, the number in between (528, 900, etc.) is always divisible by 6. - Howard Berman (howard_berman(AT)hotmail.com), Jan 02 2009

Examples

			527 = 17*31 and 529 = 23*23. Both are composite with no prime factor less than 13 and they differ by 2.

Links

Crossrefs

Cf. A038512.

Programs

  • Mathematica
    q[n_] := AllTrue[n + {0, 2}, CompositeQ[#] && FactorInteger[#][[1, 1]] >= 13 &]; Flatten @ Outer[Plus, Select[Range[3500], q], {0, 2}] (* Amiram Eldar, Mar 22 2021 *)

Extensions

More terms from Amiram Eldar, Mar 22 2021

A155511 Members of A038512 of the form k, k+2, k+6, k+8.

Original entry on oeis.org

4181, 4183, 4187, 4189, 4841, 4843, 4847, 4849, 6401, 6403, 6407, 6409, 14801, 14803, 14807, 14809, 15941, 15943, 15947, 15949, 16391, 16393, 16397, 16399, 19091, 19093, 19097, 19099, 19511, 19513, 19517, 19519, 19631, 19633, 19637, 19639, 24581, 24583, 24587, 24589
Offset: 1

Views

Author

Howard Berman (howard_berman(AT)hotmail.com), Jan 23 2009

Keywords

Comments

In each set of 4, k+4 (4185, 4845, 6405, etc.) is always divisible by 15.

Examples

			4841 = 47*103, 4843 = 29*167, 4847 = 37*131 and 4849 = 13*373. All are composite with no prime factor less than 13 and they form a sequence k, k+2, k+6, k+8.

Links

Crossrefs

Cf. A038512.

Programs

  • Mathematica
    q[n_] := AllTrue[n + {0, 2, 6, 8}, CompositeQ[#] && FactorInteger[#][[1, 1]] >= 13 &]; Flatten @ Outer[Plus, Select[Range[25000], q], {0, 2, 6, 8}] (* Amiram Eldar, Mar 22 2021 *)

Extensions

Missing terms inserted by Amiram Eldar, Mar 22 2021
Showing 1-2 of 2 results.

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

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