A137293 a(1) = 1. After the initial 1, follow with runs of integers; the n-th run of 2*a(n) terms is (1,2,3,4,....,2a(n)).

1, 1, 2, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 3, 4, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 3, 4, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 1, 2, 3, 4, 1, 2, 1, 2, 3, 4, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6, 7, 8, 1, 2, 1, 2, 3, 4, 1, 2, 3, 4, 5, 6, 1, 2, 3, 4, 5, 6

Offset

1,3

Links

John Tyler Rascoe, Table of n, a(n) for n = 1..8189 (runs for n = 1..783)

Example

Runs of integers bracketed by parentheses. (Note that n-th run {after the initial 1} has exactly 2a(n) terms.)
1, (1, 2), (1, 2), (1, 2, 3, 4), (1, 2), (1, 2, 3, 4), (1, 2), (1, 2, 3, 4), (1, 2, 3, 4, 5, 6), (1, 2, 3, 4, 5, 6, 7, 8), (1, 2), (1, 2, 3, 4), (1, 2), (1, 2, 3, 4), (1, 2, 3, 4, 5, 6), (1, 2, 3, 4, 5, 6, 7, 8), (1, 2), (1, 2, 3, 4), (1, 2), (1, 2, 3, 4), (1, 2, 3, 4, 5, 6), (1, 2, 3, 4, 5, 6, 7, 8), (1, 2), (1, 2, 3, 4), (1, 2, 3, 4, 5, 6), (1, 2, 3, 4, 5, 6, 7, 8), (1, 2, 3, 4, 5, 6, 7, 8, 9, 10), (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12), ...

Prog

(Python)
def A137293_gen(nrun):
    A = [1]
    for n in range(1, nrun+1):
        for i in range(1, (A[n-1]*2)+1): A.append(i)
    return A # John Tyler Rascoe, Mar 11 2023

Crossrefs

Cf. A136109.

Sequence in context: A330241 A175851 A049711 * A378636 A366254 A177803

Adjacent sequences: A137290 A137291 A137292 * A137294 A137295 A137296

Keyword

nonn,look,easy

Author

Leroy Quet, Mar 15 2008

Status

approved