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A060190 A diagonal of A060187. 1
1, 76, 1682, 23548, 259723, 2485288, 21707972, 178300904, 1403080725, 10708911188, 79944249686, 587172549764, 4261002128223, 30644790782352, 218917362275080, 1556000598766224, 11017646288488233, 77790282457881756 (list; graph; refs; listen; history; text; internal format)
OFFSET

4,2

LINKS

Table of n, a(n) for n=4..21.

P. A. MacMahon, The divisors of numbers, Proc. London Math. Soc., (2) 19 (1921), 305-340; Coll. Papers II, pp. 267-302.

MATHEMATICA

r[n_, k_] := r[n, k] = If[n == 0, If[k == 0, 1, 0], (2*(n-k)+1)*r[n-1, k-1] + (2*k+1)*r[n-1, k]]; A060189[n_] := r[n-1, 3]; Table[A060189[n], {n, 4, 21}] (* Jean-Fran├žois Alcover, Dec 03 2013, translated from Peter Luschny's Sage program *)

PROG

(Sage)

r := proc(n, k) option remember;

if n = 0 then if k = 0 then 1 else 0 fi else

(2*(n-k)+1)*r(n-1, k-1) + (2*k+1)*r(n-1, k) fi end:

A060189 := n -> r(n-1, 3): seq(A060189(n), n = 4..21); # Peter Luschny, May 06 2013

CROSSREFS

Sequence in context: A163710 A061618 A185819 * A156399 A232830 A153177

Adjacent sequences:  A060187 A060188 A060189 * A060191 A060192 A060193

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Mar 20 2001

EXTENSIONS

More terms from Vladeta Jovovic, Mar 20 2001

STATUS

approved

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Last modified December 22 12:59 EST 2014. Contains 252357 sequences.