|
| |
|
|
A051747
|
|
n*(n+1)*(n+2)*(n^2+7*n+32)/120.
|
|
4
| |
|
|
2, 10, 31, 76, 161, 308, 546, 912, 1452, 2222, 3289, 4732, 6643, 9128, 12308, 16320, 21318, 27474, 34979, 44044, 54901, 67804, 83030, 100880, 121680, 145782, 173565, 205436, 241831, 283216, 330088, 382976, 442442, 509082, 583527, 666444, 758537
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
LINKS
| Vincenzo Librandi, Table of n, a(n) for n = 1..1000
|
|
|
FORMULA
| a(n)=binomial(n+4, n-1)+binomial(n+2, n-1)
Convolution of triangular numbers with triangular numbers + 1, i.e. [1, 3, 6, 10, 15, 21, ...] with [2, 4, 7, 11, 16, 22, ...]
|
|
|
MATHEMATICA
| Table[(1/120)*n*(n + 1)*(n + 2)*(n^2 + 7*n + 32), {n, 60}] (* From Vladimir Joseph Stephan Orlovsky, Jun 14 2011 *)
|
|
|
PROG
| (PARI) conv(u, v)=local(w); w=vector(length(u), i, sum(j=1, i, u[j]*v[i+1-j])); w; t(n)=n*(n+1)/2; u=vector(10, i, t(i)); v=vector(10, i, t(i)+1); conv(u, v)
(MAGMA) [n*(n+1)*(n+2)*(n^2+7*n+32)/120: n in [1..40]]; // Vincenzo Librandi, Jun 15 2011
|
|
|
CROSSREFS
| Cf. A000217, A000389, A005583.
Sequence in context: A162249 A156492 A090809 * A193008 A024456 A197452
Adjacent sequences: A051744 A051745 A051746 * A051748 A051749 A051750
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Klaus Strassburger (strass(AT)ddfi.uni-duesseldorf.de), Dec 07 1999
|
| |
|
|
