A181940 a(0)=0, and there are a(n) terms between a(n) and the nearest a(n)+1.

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

Offset

0,4

Links

Table of n, a(n) for n=0..104.

Formula

a(A000217(n))=n.

Example

From Peter Luschny, May 30 2020: (Start)
Seen as a triangle:
[0]
[1, 0]
[2, 0, 1]
[3, 1, 0, 2]
[4, 2, 0, 1, 3]
[5, 3, 1, 0, 2, 4]
[6, 4, 2, 0, 1, 3, 5]
[7, 5, 3, 1, 0, 2, 4, 6]
[8, 6, 4, 2, 0, 1, 3, 5, 7]
[9, 7, 5, 3, 1, 0, 2, 4, 6, 8]
[10, 8, 6, 4, 2, 0, 1, 3, 5, 7, 9]
[11, 9, 7, 5, 3, 1, 0, 2, 4, 6, 8, 10]
(End)

Prog

(PARI) a_list(N)={my(a=vector(2*N), c=0); for(i=2, N, a[i]=c++; my(j=i); for(k=1, c-1, a[j-=(-1)^k*(c-k+1)]=c-k); i+=c); vecextract(a, 2^N-1)}
(Python)
def T(num_rows):
    L, R = [0], [0]
    for n in range(1, num_rows):
        R.reverse()
        R.insert(0, n)
        L.extend(R)
    return L
print(T(14)) # Peter Luschny, May 30 2020

Crossrefs

Sequence in context: A137712 A194711 A168532 * A356154 A261209 A340006

Adjacent sequences: A181937 A181938 A181939 * A181941 A181942 A181943

Keyword

nonn

Author

Eric Angelini and M. F. Hasler, Apr 03 2012

Status

approved