cp's OEIS Frontend

A358406 The index of A358405 where n first appears, or 0 if n never appears.

%I A358406 #10 Nov 14 2022 09:59:39
%S A358406 1,3,5,10,16,8,19,141,14,190,25,22,416,70,54,162,32,308,169,67,93,203,
%T A358406 118,513,196,29,40,200,861,37,74,1081,82,216,208,363,90,46,375,1675,
%U A358406 1091,333,1407,812,166,78,51,1099,115,193,1243,64,595,98,58,367,617,235,325,766,2137,272,124
%N A358406 The index of A358405 where n first appears, or 0 if n never appears.
%C A358406 See A358405 for further details.
%o A358406 (Python)
%o A358406 from itertools import count, islice
%o A358406 def agen():
%o A358406     k, an, first, prev = 0, 0, {0: 1}, {0: 1}
%o A358406     for n in count(2):
%o A358406         while k in first: yield first[k]; k += 1
%o A358406         an1 = 0 if first[an] == n-1 else max(n-1-prev[an], first[an])
%o A358406         if an1 not in first: first[an1] = prev[an1] = n
%o A358406         prev[an] = n-1
%o A358406         an = an1
%o A358406 print(list(islice(agen(), 63))) # _Michael S. Branicky_, Nov 14 2022
%Y A358406 Cf. A358405, A358402, A358403, A181391.
%K A358406 nonn
%O A358406 0,2
%A A358406 _Scott R. Shannon_, Nov 14 2022