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A056000 n*(n+9)/2. 21
0, 5, 11, 18, 26, 35, 45, 56, 68, 81, 95, 110, 126, 143, 161, 180, 200, 221, 243, 266, 290, 315, 341, 368, 396, 425, 455, 486, 518, 551, 585, 620, 656, 693, 731, 770, 810, 851, 893, 936, 980, 1025, 1071, 1118, 1166, 1215, 1265, 1316, 1368, 1421, 1475 (list; graph; refs; listen; history; internal format)
OFFSET

0,2

COMMENTS

a(n)=A000096 + 3 * A001477, a(n)=A055999 + A001477 and a(n)=A056115 - A001477 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 01 2006

a(n) = A126890(n,4) for n>3. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Dec 30 2006

REFERENCES

A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, p. 193.

LINKS

Index entries for sequences related to linear recurrences with constant coefficients, signature (3,-3,1).

FORMULA

G.f.(x)=x(5-4x)/(1-x)^3.

a(n)=C(n,2)-4*n,n>=9 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Nov 25 2006

Equals A028569/2 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Feb 12 2007

If we define f(n,i,a)=sum(binomial(n,k)*stirling1(n-k,i)*product(-a-j,j=0..k-1),k=0..n-i), then a(n) = -f(n,n-1,5), for n>=1. [From Milan R. Janjic (agnus(AT)blic.net), Dec 20 2008]

a(n)=n+a(n-1)+4. [From Vincenzo Librandi (vincenzo.librandi(AT)tin.it), Aug 07 2010]

a(n)= sum((k+4)!/(k+3)!,k=1..n) [From Gary Detlefs (gdetlefs(AT)aol.com), Aug 10 2010]

MATHEMATICA

lst={}; Do[AppendTo[lst, n*(n+9)/2], {n, 0, 5!}]; lst ...and/or... s=0; lst={s}; Do[s+=n+1; AppendTo[lst, s], {n, 4, 5!}]; lst [From Vladimir Orlovsky (4vladimir(AT)gmail.com), Oct 25 2008]

CROSSREFS

Equals A000217(n+4)-10. Cf. A000096, A055998 and A055999.

Column m=2 of (1, 5)-Pascal triangle A096940.

Cf. A000096, A055998, A001477.

Cf. numbers of the form n*(d*n+10-d)/2 indexed in A140090.

Sequence in context: A145005 A004083 A190365 * A080566 A094684 A140697

Adjacent sequences:  A055997 A055998 A055999 * A056001 A056002 A056003

KEYWORD

easy,nonn

AUTHOR

Barry E. Williams, Jun 16 2000

EXTENSIONS

More terms from James A. Sellers (sellersj(AT)math.psu.edu), Jul 04 2000

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Last modified February 17 00:09 EST 2012. Contains 205978 sequences.