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.

A358927 a(n) is the smallest tetrahedral number with exactly n prime factors (counted with multiplicity), or -1 if no such number exists.

Table of values

n a(n)
0 1
1 -1
2 4
3 20
4 56
5 120
6 560
7 4960
8 19600
9 41664
10 341376
11 695520
12 7207200
13 22238720
14 178433024
15 1429559296
16 179481600
17 11453245440
18 11444858880
19 393079864320
20 3928874471424
21 5864598896640
22 46910348656640
23 975649558118400
24 3002365391929344
25 7805131503206400

List of values

[1, -1, 4, 20, 56, 120, 560, 4960, 19600, 41664, 341376, 695520, 7207200, 22238720, 178433024, 1429559296, 179481600, 11453245440, 11444858880, 393079864320, 3928874471424, 5864598896640, 46910348656640, 975649558118400, 3002365391929344, 7805131503206400]

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

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