|
%I #23 Apr 08 2023 11:17:54
%S 1,2,2,3,3,4,4,5,4,6,5,7,6,7,7,7,8,8,8,9,8,10,8,11,9,11,10,11,10,11,
%T 11,12,11,13,11,14,11,15,11,16,11,17,11,18,11,18,12,18,13,18,13,18,14,
%U 18,14,19,14,20,14,20,15,19,16,20,16,20,16,21,17,21,17,21,18,21,18,22,18
%N a(0)=1, a(n) = ceiling(prime(n)/a(n-1)), where prime(n) is the n-th prime.
%C With floor instead of ceiling, we get 1, 2, 1, 5, 1, 11, 1, 17, 1, 23, ..., which is A031368 interspersed with 1's. - _Michel Marcus_, Apr 08 2023
%H John Tyler Rascoe, <a href="/A140828/b140828.txt">Table of n, a(n) for n = 0..10000</a>
%t a = {1}; For[n = 1, n < 80, n++, AppendTo[a, Ceiling[Prime[n]/a[[n]]]]]; a (* _Stefan Steinerberger_, Aug 28 2008 *)
%o (Python)
%o from math import ceil
%o from sympy import prime
%o def A140828_list(nmax):
%o A = [1]
%o for n in range(1,nmax+1):
%o A.append(ceil(prime(n)/A[-1]))
%o return A # _John Tyler Rascoe_, Apr 07 2023
%o (PARI) lista(nn) = my(va = vector(nn)); va[1] = 1; for (n=2, nn, va[n] = ceil(prime(n-1)/va[n-1]);); va; \\ _Michel Marcus_, Apr 08 2023
%Y Cf. A140829 (similar sequence).
%Y Cf. A031368.
%K nonn
%O 0,2
%A _Leroy Quet_, Jul 18 2008
%E More terms from _Stefan Steinerberger_, Aug 28 2008
|
