A348408 a(n) is the length of the n-th row of A348433 when it is written as an irregular triangle.

5, 2, 9, 8, 8, 10, 11, 22, 11, 16, 10, 14, 22, 29, 22, 26, 20, 27, 28, 26, 41, 36, 46, 42, 40, 42, 46, 42, 48, 44, 73, 62, 52, 53, 68, 69, 60, 67, 78, 73, 71, 86, 67, 80, 70, 96, 85, 88, 83, 80, 94, 84, 95, 96, 103, 101, 100, 110, 94, 113, 109, 120, 118, 126

Offset

1,1

Links

Michael De Vlieger, Table of n, a(n) for n = 1..5000

Example

When A348433 is written as an irregular triangle the first three rows are:
  1, 2, 4, 8, 16;
  7, 14;
  5, 10, 20, 40, 80, 160, 320, 640, 1280;
The lengths of the rows are [5, 2, 9] respectively, the same as the first three terms of this sequence.

Mathematica

c[1] = m = 1; Most@ Prepend[Differences[#], First[#]] &@ Reap[Do[If[IntegerQ[c[#]], Set[n, 2 m], Set[n, #]] &@ Total@ IntegerDigits[m]; If[m > n, Sow[i]]; Set[c[n], 1]; m = n, {i, 2^12}]][[-1, -1]] (* Michael De Vlieger, Oct 25 2021 *)

Prog

(PARI) lista(nn) = my(k, r, s, v=List([1])); for(n=1, nn, while(setsearch(vecsort(v), s=sumdigits(v[k++])), listput(v, 2*v[k])); listput(v, s); print1(k-r, ", "); r=k); \\ Jinyuan Wang, Oct 21 2021

Crossrefs

Cf. A348433.

Sequence in context: A097897 A063761 A255899 * A019841 A064582 A197374

Adjacent sequences: A348405 A348406 A348407 * A348409 A348410 A348411

Keyword

nonn

Author

Rodolfo Kurchan, Oct 19 2021

Extensions

More terms from Jinyuan Wang, Oct 21 2021

Status

approved