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A157059 Number of integer sequences of length n+1 with sum zero and sum of absolute values 20. 1
2, 60, 1002, 11750, 106752, 794598, 5025692, 27717948, 135916002, 601585512, 2432878866, 9079799742, 31534801116, 102644594262, 315029394792, 916470530808, 2538818182782, 6724224543708, 17088309885542, 41800229045610, 98698280879352, 225524301678170 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1000

FORMULA

a(n)=T(n,10); T(n,k)=sum({i=1..n}binomial(n+1,i)*binomial(k-1,i-1)*binomial(n-i+k,k))

G.f.: -2*x*(x^18 +9*x^17 +81*x^16 +324*x^15 +1296*x^14 +3024*x^13 +7056*x^12 +10584*x^11 +15876*x^10 +15876*x^9 +15876*x^8 +10584*x^7 +7056*x^6 +3024*x^5 +1296*x^4 +324*x^3 +81*x^2 +9*x +1) / (x -1)^21. [Colin Barker, Jan 25 2013]

CROSSREFS

Cf. A103881, A156554.

Sequence in context: A006333 A001760 A230572 * A272980 A222652 A227624

Adjacent sequences:  A157056 A157057 A157058 * A157060 A157061 A157062

KEYWORD

nonn,easy

AUTHOR

R. H. Hardin Feb 22 2009

STATUS

approved

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Last modified May 28 21:37 EDT 2020. Contains 334690 sequences. (Running on oeis4.)