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A269700
a(n) = floor( Product_{k>=0} (1 + n/k!) ).
2
1, 7, 26, 69, 151, 293, 519, 862, 1361, 2062, 3019, 4297, 5969, 8121, 10848, 14261, 18481, 23646, 29908, 37437, 46419, 57061, 69586, 84242, 101297, 121042, 143793, 169893, 199710, 233642, 272117, 315592, 364560, 419545, 481109, 549849, 626403, 711448, 805703
OFFSET
0,2
LINKS
EXAMPLE
For n=3, a(3) = floor(69.52294621467075235981513247145953...) = 69.
MATHEMATICA
Table[Floor@ Product[1 + n/k!, {k, 0, 10^2}], {n, 0, 38}] (* Michael De Vlieger, Mar 27 2016 *)
PROG
(Sidef)
func a(n) {
var (prod=1, prev=1)
for i in (0 ..^ Inf) {
prod *= (1 + n/i!)
break if (prod/prev <= 1+1e-100)
prev = prod
}
return floor(prod)
}
range(0, 100).each { |n| say a(n) }
(PARI) a(n) = floor(prodinf(k=0, 1+n/k!)); \\ Michel Marcus, Mar 04 2016
CROSSREFS
Cf. A238695.
Sequence in context: A268861 A221793 A299282 * A006325 A053346 A227021
KEYWORD
nonn,easy
AUTHOR
Daniel Suteu, Mar 03 2016
STATUS
approved