|
Search: id:A051940
|
|
|
| A051940 |
|
Truncated triangular numbers: a(n)=n*(n+1)/2-3*t*(t+1)/2, t=4. |
|
+0
2
|
|
| 6, 15, 25, 36, 48, 61, 75, 90, 106, 123, 141, 160, 180, 201, 223, 246, 270, 295, 321, 348, 376, 405, 435, 466, 498, 531, 565, 600, 636, 673, 711, 750, 790, 831, 873, 916, 960, 1005, 1051, 1098, 1146, 1195, 1245, 1296, 1348, 1401, 1455, 1510, 1566, 1623
(list; graph; listen)
|
|
|
OFFSET
|
8,1
|
|
|
COMMENT
|
Equals binomial transform of [6, 9, 1, 0, 0, 0,...] [From Gary W. Adamson (qntmpkt(AT)yahoo.com), Aug 25 2009]
|
|
FORMULA
|
a(n)=n+a(n-1)+7 (with a(1)=6) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 19 2009]
|
|
EXAMPLE
|
For n=2, a(2)=2+6+7=15; n=3, a(3)=3+15+7=25; n=4, a(4)=4+25+7=36 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 19 2009]
|
|
MATHEMATICA
|
Table[n*(n + 1)/2 - 30, {n, 8, 70}] - Stefan Steinerberger (stefan.steinerberger(AT)gmail.com), Mar 31 2006
|
|
CROSSREFS
|
a(n)=A000217(n)-30, n>7
Sequence in context: A122709 A052220 A064565 this_sequence A020207 A151762 A008440
Adjacent sequences: A051937 A051938 A051939 this_sequence A051941 A051942 A051943
|
|
KEYWORD
|
easy,nice,nonn,new
|
|
AUTHOR
|
Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 21 1999
|
|
|
Search completed in 0.002 seconds
|
