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A060293
Expected coupon collection numbers rounded up; i.e., if aiming to collect a set of n coupons, the expected number of random coupons required to receive the full set.
5
0, 1, 3, 6, 9, 12, 15, 19, 22, 26, 30, 34, 38, 42, 46, 50, 55, 59, 63, 68, 72, 77, 82, 86, 91, 96, 101, 106, 110, 115, 120, 125, 130, 135, 141, 146, 151, 156, 161, 166, 172, 177, 182, 188, 193, 198, 204, 209, 215, 220, 225, 231, 236, 242, 248, 253, 259, 264, 270
OFFSET
0,3
LINKS
FORMULA
a(n) = ceiling(n*Sum_{k=1..n}(1/k)) = ceiling(n*A001008(n)/A002805(n)) = A052488(n) + 1 for n>2.
EXAMPLE
a(2)=3 since the probability of getting both coupons after two is 1/2, after 3 is 1/4, after 4 is 1/8, etc. and 2/2 + 3/2^2 + 4/2^3 + ... = 3.
MAPLE
H := proc(n)
add(1/k, k=1..n) ;
end proc:
A060293 := proc(n)
ceil(n*H(n)) ;
end proc: # R. J. Mathar, Aug 02 2009, Dec 02 2016
A060293:= n -> ceil(Psi(n+1)+gamma); # Robert Israel, May 19 2014
MATHEMATICA
f[n_] := Ceiling[n*HarmonicNumber[n]]; Array[f, 60, 0] (* Robert G. Wilson v, Nov 23 2015 *)
PROG
(PARI) vector(100, n, n--; ceil(n*sum(k=1, n, 1/k))) \\ Altug Alkan, Nov 23 2015
(Python)
from math import ceil
n=100 #number of terms
ans=0
finalans = [0]
for i in range(1, n+1):
ans+=(1/i)
finalans.append(ceil(ans*i))
print(finalans)
# Adam Hugill, Feb 14 2022
CROSSREFS
Cf. A052488.
Sequence in context: A070021 A083354 A156242 * A336803 A220657 A194273
KEYWORD
easy,nonn
AUTHOR
Henry Bottomley, Mar 24 2001
STATUS
approved