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A027804 a(n) = 14*(n+1)*C(n+4,8). 0
70, 756, 4410, 18480, 62370, 180180, 462462, 1081080, 2342340, 4764760, 9189180, 16930368, 29980860, 51279480, 85058820, 137287920, 216228474, 333125100, 503052550, 745945200, 1087836750, 1562340780, 2212405650 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,1

LINKS

Table of n, a(n) for n=4..26.

Index entries for linear recurrences with constant coefficients, signature (10,-45,120,-210,252,-210,120,-45,10,-1).

FORMULA

Number of 13-subsequences of [ 1, n ] with just 4 contiguous pairs; g.f. 14*(5+4x)*x^4/(1-x)^10.

a(n) = C(n+1, 5)*C(n+4, 4). - Zerinvary Lajos, May 10 2005, corrected by R. J. Mathar, Feb 10 2016

CROSSREFS

Sequence in context: A199829 A271495 A232587 * A212236 A177298 A230897

Adjacent sequences:  A027801 A027802 A027803 * A027805 A027806 A027807

KEYWORD

nonn,easy

AUTHOR

thi ngoc dinh (via R. K. Guy)

STATUS

approved

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Last modified July 20 11:28 EDT 2019. Contains 325180 sequences. (Running on oeis4.)