A253425 Lengths of runs of identical terms in A253415.

1, 1, 6, 11, 18, 12, 5, 22, 91, 143, 1, 93, 370, 182, 20, 20, 315, 332, 973, 157, 1223, 1807, 325, 4044, 7412, 11211, 4600, 2176, 14848, 4659, 3123, 10852, 1678, 20862, 3348

Offset: 1

Author

Reinhard Zumkeller, Dec 31 2014

Keywords

• nonn
• more

Crossrefs

Cf. A253415, A095258.

Programs

Haskell

import Data.List (group)
a253425 n = a253425_list !! (n-1)
a253425_list = map length $ group a253415_list

Mathematica

c[] = 0; c[1] = j = 1; u = 2; s = 3; Most@ Tally[#][[All, -1]] &@ Reap[Do[d = Divisors[s]; k = 1; While[c[d[[k]]] > 0, k++]; Set[k, d[[k]]]; Set[c[k], i]; If[k == u, While[c[u] > 0, u++]]; Sow[u]; j = k; s += k, {i, 2, 2^12}]][[-1, -1]] (* _Michael De Vlieger, Jan 23 2022 *)

Python

from itertools import islice
from sympy import divisors
def A253425_gen(): # generator of terms
    bset, l, m, s = {1}, 0, 2, 3
    while True:
        for d in divisors(s):
            if d not in bset:
                bset.add(d)
                if m in bset:
                    yield l
                    l = 1
                    while m in bset:
                        m += 1
                else:
                    l += 1
                s += d
                break
A253425_list = list(islice(A253425_gen(),20)) # Chai Wah Wu, Jan 25 2022

Extensions

a(14)-a(35) from Michael De Vlieger, Jan 23 2022