The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A358405 a(1) = 0; for n > 1, let a(n-1) = m; if a(n-1) is the first occurrence of m then a(n) = 0, but if there is a k < n-1 with a(k) = m, a(n) is the maximum of n-1-k and j, where a(j) is the first occurrence of m in the sequence. 4
 0, 0, 1, 0, 2, 0, 2, 5, 0, 3, 0, 2, 5, 8, 0, 4, 0, 2, 6, 0, 3, 11, 0, 3, 10, 0, 3, 10, 25, 0, 4, 16, 0, 3, 10, 25, 29, 0, 5, 26, 0, 3, 10, 25, 29, 37, 0, 6, 29, 37, 46, 0, 5, 14, 0, 3, 14, 54, 0, 4, 29, 37, 46, 51, 0, 6, 19, 0, 3, 13, 0, 3, 10, 30, 0, 4, 16, 45, 0, 4, 16, 32, 0, 4, 16, 32, 82 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,5 COMMENTS This sequence uses the same selection rules as A358402 but here the maximum of the two offsets is chosen for a(n). The terms form an unusual pattern for larger values of n; see the linked images. See A358406 for the index where each number first appears. LINKS Scott R. Shannon, Table of n, a(n) for n = 1..10000. Scott R. Shannon, Image of the first 100000 terms. Scott R. Shannon, Image of the first 1000000 terms. Scott R. Shannon, Image of the first 10000000 terms. EXAMPLE a(5) = 2 as a(4) = 0 and a(2) = 0, these being separated by two terms. a(8) = 5 as a(7) = 2 and 2 appears as the fifth term of the sequence. Note that the number of terms between the two previous occurrences of 2 is 7 - 5 = 2 which is smaller than 5, so 5 is chosen. MATHEMATICA nn = 120; q[_] = c[_] = 0; m = a[1] = 0; Do[If[c[#] == 0, k = 0; c[#] = q[#] = n - 1, k = Max[n - 1 - c[#], q[#]]; c[#] = n - 1] &[m]; a[n] = m = k; If[k == u, While[c[u] > 0, u++]], {n, 2, nn}]; Array[a, nn] PROG (Python) from itertools import count, islice def agen(): an, first, prev = 0, {0: 1}, {0: 1} for n in count(2): yield an an1 = 0 if first[an] == n-1 else max(n-1-prev[an], first[an]) if an1 not in first: first[an1] = prev[an1] = n prev[an] = n-1 an = an1 print(list(islice(agen(), 87))) # Michael S. Branicky, Nov 14 2022 CROSSREFS Cf. A358406, A181391, A358402, A358403, A171862, A171863. Sequence in context: A279327 A052438 A324045 * A209701 A158855 A344908 Adjacent sequences: A358402 A358403 A358404 * A358406 A358407 A358408 KEYWORD nonn,look AUTHOR Scott R. Shannon, Nov 14 2022 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified August 3 19:29 EDT 2024. Contains 374909 sequences. (Running on oeis4.)