A277904 - OEIS

%I #11 Nov 16 2016 11:08:03

%S 0,0,0,1,0,1,0,1,2,3,0,1,2,3,0,1,2,3,4,5,0,1,2,3,4,5,0,1,2,3,4,5,6,7,

%T 8,9,0,1,2,3,4,5,6,7,8,9,0,1,2,3,4,5,6,7,8,9,10,11,12,13,0,1,2,3,4,5,

%U 6,7,8,9,10,11,12,13,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19

%N Irregular table: row n (n >= 0) is obtained by listing numbers 0 .. A018819(n)-1.

%H Antti Karttunen, <a href="/A277904/b277904.txt">Table of n, a(n) for n = 1..9828</a>

%F a(1) = 0; for n > 1, a(n) = n - A000123(A277903(n)-1) - 1.

%e A018819 -> range -> terms on row n

%e   1        [0,0]:    0;

%e   1        [0,0]:    0;

%e   2        [0,1]:    0, 1;

%e   2        [0,1]:    0, 1;

%e   4        [0,3]:    0, 1, 2, 3;

%e   4        [0,3]:    0, 1, 2, 3;

%e   6        [0,5]:    0, 1, 2, 3, 4, 5;

%e etc.

%o (Scheme) (define (A277904 n) (if (= 1 n) 0 (- n (A000123 (+ -1 (A277903 n))) 1)))

%Y Cf. A000123, A018819, A277903.

%Y Used for constructing A277905.

%Y Retaining only every second row gives A278164.

%K nonn,tabf

%O 1,9

%A _Antti Karttunen_, Nov 14 2016