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a(n) is the length of the n-th row of A348575.
3

%I #49 Jan 01 2022 00:17:16

%S 9,28,100,3660,2,4,34,279,1342,24486,41,4,9,37,3373,30332,10768,89207,

%T 9888780,118322,103912,1083421,1095431404,1182371,33970573,116430219,

%U 3152744167,24330557,27560841783

%N a(n) is the length of the n-th row of A348575.

%C Terms computed by _Claudio Meller_.

%e When A348575 is written as an irregular triangle, the first three rows are:

%e 1, ..., 37: 9 terms

%e 10, ..., 388: 28 terms

%e 19, ..., 4969: 100 terms

%e The lengths of the rows are [9, 28, 100] respectively, the same as the first three terms of this sequence.

%e a(30) exceeds 4242640687120 (perhaps by orders of magnitude); see A349548. - _Jon E. Schoenfield_, Nov 29 2021

%t seq[len_] := Module[{s = {1}, sq = {}, i = 1, d}, While[Length[sq] < len, If[MemberQ[s, (d = Plus @@ IntegerDigits[s[[-1]]])], AppendTo[s, s[[-1]] + i], AppendTo[s, d]; AppendTo[sq, i]; i = 0]; i++]; sq]; seq[15] (* _Amiram Eldar_, Nov 23 2021 *)

%Y Cf. A348575, A349548.

%K nonn,base,hard,more

%O 1,1

%A _Rodolfo Kurchan_, Nov 21 2021

%E a(23)-a(29) from _Jon E. Schoenfield_, Nov 30 2021