|
Search: id:A115067
|
|
| |
|
| 0, 4, 11, 21, 34, 50, 69, 91, 116, 144, 175, 209, 246, 286, 329, 375, 424, 476, 531, 589, 650, 714, 781, 851, 924, 1000, 1079, 1161, 1246, 1334, 1425, 1519, 1616, 1716, 1819, 1925, 2034, 2146, 2261, 2379, 2500, 2624, 2751, 2881, 3014, 3150, 3289, 3431, 3576
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
LINKS
|
Alfred Hoehn, Illustration of initial terms of A000326, A005449, A045943, A115067
|
|
FORMULA
|
Sum (n+j,j=2..n). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 12 2006
sum(igcd(n+j,n+j),j=2..n). - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 05 2006
If offset = 0 then a(n) = (3*n^2 + 5*n)/2 = n(3n + 5)/2. - Omar E. Pol (info(AT)polprimos.com), May 21 2008
a(n)=3*n+a(n-1)-2 (with a(1)=0) [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
|
|
EXAMPLE
|
For n=2, a(2)=3*2+0-2=4; n=3, a(3)=3*3+4-2=11; n=4, a(4)=3*4+11-2=21 [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Nov 08 2009]
|
|
MAPLE
|
a:=n->sum(igcd(n+j, n+j), j=2..n): seq(a(n), n=1..49); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 05 2006
with(finance):seq(add(cashflows([2, k, n], 0 ), k=1..n), n=0..50); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Jun 22 2008
a:=n->sum(k+sum(1, k=1..n), k=2..n):seq(a(n), n=1...43); [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Aug 24 2008]
|
|
MATHEMATICA
|
lst={}; Do[AppendTo[lst, (3*n^2-n-2)/2], {n, 5!}]; lst ...and/or... s=-1; lst={}; Do[s+=n+1; AppendTo[lst, s], {n, 0, 6!, 3}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 25 2008]
|
|
CROSSREFS
|
The generalized pentagonal numbers b*n+3*n*(n-1)/2, for b = 1 through 12, form sequences A000326, A005449, A045943, A115067, A140090, A140091, A059845, A140672, A140673, A140674, A140675, A151542.
Sequence in context: A008052 A016438 A038427 this_sequence A009893 A027369 A008008
Adjacent sequences: A115064 A115065 A115066 this_sequence A115068 A115069 A115070
|
|
KEYWORD
|
nonn,new
|
|
AUTHOR
|
Roger Bagula (rlbagulatftn(AT)yahoo.com), Mar 01 2006
|
|
EXTENSIONS
|
Edited by N. J. A. Sloane (njas(AT)research.att.com), Mar 05 2006
|
|
|
Search completed in 0.002 seconds
|
