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.

A278569 Numbers of the form p^i*q^j*r^k where p,q,r are distinct odd primes and i,j,k >= 1.

Original entry on oeis.org

105, 165, 195, 231, 255, 273, 285, 315, 345, 357, 385, 399, 429, 435, 455, 465, 483, 495, 525, 555, 561, 585, 595, 609, 615, 627, 645, 651, 663, 665, 693, 705, 715, 735, 741, 759, 765, 777, 795, 805, 819, 825, 855, 861, 885, 897, 903, 915, 935, 945, 957, 969, 975, 987, 1001, 1005, 1015, 1023, 1035, 1045, 1065, 1071, 1085, 1095, 1105, 1113, 1131, 1173, 1185, 1197, 1209
Offset: 1

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Author

N. J. A. Sloane, Nov 27 2016

Keywords

Comments

More than the usual number of terms are included to show the difference from A216918 (the latter includes 3*5*7*11 = 1155 and all terms of A046390, A046391 etc).
If i,j,k are all equal to 1 we get A046389.

Crossrefs

Includes A046389, subsequence of A216918.

Programs

  • Mathematica
    Select[Range@ 1500, PrimeNu@ # == 3 && OddQ@ # &] (* Michael De Vlieger, Dec 05 2016 *)

Formula

A033992 INTERSECT A005408. - R. J. Mathar, Dec 05 2016