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A180600 a(n+1) = a(n) if A180458(n+1) = A180458(n), otherwise a(n+1) = a(n)+1. 1
1, 2, 3, 4, 5, 5, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10, 10, 11, 11, 12, 12, 13, 13, 13, 13, 14, 15, 16, 16, 16, 17, 18, 18, 19, 19, 20, 20, 21, 22, 22, 22, 22, 23, 24, 24, 24, 25, 25, 25, 26, 27, 28, 28, 28, 29, 29, 30, 31, 32, 32, 33, 33, 34, 35, 36, 36, 37, 37, 38, 39, 39, 40, 40, 41 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

This arithmetic sequence grows with slope 1 where A180458 increases, and has terraces (zero slope) where A180458 has terraces.

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

FORMULA

a(n+1) = a(n) + min(1, A180458(n+1)-A180458(n)). - R. J. Mathar, Oct 24 2010

MAPLE

isA002113 := proc(n) n = digrev(n) ; end proc:

A180458 := proc(n) local p ; p := ithprime(n) ; while not isA002113(p) do p := p-1 ; end do; p ; end proc:

A180600 := proc(n) option remember; if n = 1 then 1; else if A180458(n) = A180458(n-1) then procname(n-1) ; else procname(n-1)+1 ; end if; end if; end proc:

seq(A180600(n), n=1..90) ; # R. J. Mathar, Oct 24 2010

MATHEMATICA

lpn[n_]:=Module[{k=0}, While[!PalindromeQ[n-k], k++]; n-k]; nxt[{n_, l_, a_}] := Module[{x=lpn[Prime[n+1]]}, {n+1, x, If[x==l, a, a+1]}]; NestList[ nxt, {1, 1, 1}, 80][[All, 3]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Dec 18 2020 *)

CROSSREFS

Sequence in context: A087829 A078474 A087177 * A006159 A081610 A063273

Adjacent sequences:  A180597 A180598 A180599 * A180601 A180602 A180603

KEYWORD

easy,nonn,base

AUTHOR

Giovanni Teofilatto, Sep 11 2010

EXTENSIONS

Sequence corrected starting near a(54), definition corrected, comment and formula added by R. J. Mathar, Oct 24 2010

STATUS

approved

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Last modified January 21 22:08 EST 2022. Contains 350480 sequences. (Running on oeis4.)