A249728 - OEIS

%I #9 Nov 24 2018 15:31:09

%S 1,2,3,3,4,4,5,5,5,6,6,6,7,7,7,7,8,8,8,8,9,9,9,9,10,10,10,10,11,11,11,

%T 11,11,12,12,12,12,12,13,13,13,13,13,13,14,14,14,14,14,14,15,15,15,15,

%U 15,15,16,16,16,16,16,16,17,17,17,17,17,17,17,18,18,18,18,18,18,18,19,19,19,19,19,19,19,19,20,20,20,20,20,20,20,20

%N After a(1) = 1 each n appears A000720(n) times.

%H Antti Karttunen, <a href="/A249728/b249728.txt">Table of n, a(n) for n = 1..10016</a>

%t Join[{1},Table[Table[n,PrimePi[n]],{n,20}]//Flatten] (* _Harvey P. Dale_, Nov 24 2018 *)

%o (Scheme, with _Antti Karttunen_'s IntSeq-library)

%o (define A249727 (COMPOSE (LEAST-GTE-I 0 1 A046992) -1+)) ;; One-based.

%Y Cf. A000720, A046992, A249727, A249809.

%K nonn

%O 1,2

%A _Antti Karttunen_, Nov 06 2014