The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A224525 Number of idempotent 3 X 3 0..n matrices of rank 1. 2
 27, 69, 123, 195, 273, 375, 477, 603, 735, 885, 1035, 1221, 1395, 1593, 1803, 2031, 2253, 2511, 2757, 3039, 3321, 3615, 3909, 4251, 4575, 4917, 5271, 5649, 6015, 6429, 6819, 7245, 7671, 8109, 8559, 9051, 9513, 9999, 10497, 11031, 11541, 12099, 12633 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Row 3 of A224524. LINKS Robert Israel, Table of n, a(n) for n = 1..10000 (first 80 terms from R. H. Hardin) FORMULA a(n) = 6*n^2 + 18*n + 3 + 6 * A002541(n). - Robert Israel, Dec 15 2019 EXAMPLE Some solutions for n=3: 0 1 0 1 3 2 0 1 0 1 3 1 0 0 0 0 0 0 1 0 0 0 1 0 0 0 0 0 1 0 0 0 0 0 1 2 3 0 3 1 0 0 0 3 0 0 0 0 0 2 0 0 0 0 0 0 0 1 0 1 2 0 0 MAPLE f:= k -> 6*k^2 + 18*k + 3 + 6 * add(floor(k/m), m=2..k): map(f, [\$1..50]); # Robert Israel, Dec 15 2019 CROSSREFS Cf. A002541, A224524. Sequence in context: A065008 A250134 A116353 * A219130 A116302 A181976 Adjacent sequences: A224522 A224523 A224524 * A224526 A224527 A224528 KEYWORD nonn AUTHOR R. H. Hardin, Apr 09 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 22 10:51 EDT 2024. Contains 371897 sequences. (Running on oeis4.)