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 A324787 Index of n-th low point in A022837. 5
 2, 5, 12, 29, 78, 199, 508, 1355, 3592, 9589, 25752, 70579, 194228, 539961, 1507602, 4228745, 11913940, 33690443, 95581182, 272003821, 776082524, 2219823175, 6363074656 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,1 COMMENTS A "low point" in a sequence is a term which is less than the previous term (this condition is skipped for the initial term) and which is followed by two or more increases. LINKS Rémy Sigrist, PARI program for A324787 MAPLE Riecaman := proc(a, s, M) # Start with s, add or subtract a[n], get M terms. If a has w terms, can get M=w+1 terms. local b, M2, n, t; if whattype(a) <> list then ERROR("First argument should be a list"); fi; if a=0 then ERROR("a should not be zero"); fi; M2 := min(nops(a), M-1); b:=[s]; t:=s; for n from 1 to M2 do    if a[n]>t then t:=t+a[n] else t:=t-a[n]; fi; b:=[op(b), t]; od: b; end; blocks := proc(a, S) local b, c, d, M, L, n; # Given a list a, whose leading term has index S, return [b, c, d], where b lists the indices of the low points in a, c lists the values of a at the low points, and d lists the length of runs between the low points. b:=[]; c:=[]; d:=[]; L:=1; # if a a low point?    n:=1;    if( (a[n+1]>a[n]) and (a[n+2]>a[n+1]) ) then    b:=[op(b), n+S-1]; c:=[op(c), a[n]]; d:=[op(d), n-L]; L:=n; fi; for n from 2 to nops(a)-2 do # if a[n] a low point?    if( (a[n-1]>a[n]) and (a[n+1]>a[n]) and (a[n+2]>a[n+1]) ) then    b:=[op(b), n+S-1]; c:=[op(c), a[n]]; d:=[op(d), n-L]; L:=n; fi; od; [b, c, d]; end; p0:=[seq(ithprime(n), n=1..100001)]: q1:=Riecaman(p0, 1, 100000): blocks(q1, 0); # produces [the present sequence, A324788, A324789] PROG (PARI) See Links section. CROSSREFS Cf. A022837, A324788, A324789, A324790. If the basic sequence (A022837) began with 0 instead of 1 we would get A008348, A309226, A324782, A324783, A309225. Sequence in context: A152171 A132807 A261234 * A333888 A228516 A101411 Adjacent sequences:  A324784 A324785 A324786 * A324788 A324789 A324790 KEYWORD nonn,more AUTHOR N. J. A. Sloane, Sep 04 2019 EXTENSIONS Modified definition to make offset 0. - N. J. A. Sloane, Oct 02 2019 a(12)-a(22) from Rémy Sigrist, Oct 18 2020 STATUS approved

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Last modified September 26 06:16 EDT 2021. Contains 347664 sequences. (Running on oeis4.)