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A258862 Second pi-based antiderivative of n: the least m such that A258851^2(m) equals n. 6
0, 3, 5, 11, 4, 10, 41, 13, 15, 83, 109, 29, 19, 35, 191, 43, 30, 277, 74, 14, 8, 42, 77, 431, 461, 21, 22, 563, 66, 599, 26, 78, 12, 61, 141, 163, 877, 18, 214, 218, 226, 38, 114, 201, 105, 1201, 215, 1297, 302, 55, 1447, 1471, 89, 25, 103, 170, 58, 291, 51 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Alois P. Heinz, Table of n, a(n) for n = 0..10000

FORMULA

a(n) = min { m >= 0 : A258851^2(m) = n }.

A258851^2(a(n)) = A258852(a(n)) = n.

a(n) <= A000040^2(n) for n>0.

a(n) <= A258861^2(n); a(21) = 42 < A258861^2(21) = A258861(22) = 79; A258851^2(42) = A258851^2(79) = 21.

MAPLE

with(numtheory):

d:= n-> n*add(i[2]*pi(i[1])/i[1], i=ifactors(n)[2]):

a:= proc() local t, a; t, a:= -1, proc() -1 end;

      proc(n) local h;

        while a(n) = -1 do

          t:= t+1; h:= d(d(t));

          if a(h) = -1 then a(h):= t fi

        od; a(n)

      end

    end():

seq(a(n), n=0..100);

CROSSREFS

Column k=2 of A259016.

Cf. A000040, A000720, A258851, A258852, A258861, A258995.

Sequence in context: A064523 A268034 A286567 * A139430 A143386 A214862

Adjacent sequences:  A258859 A258860 A258861 * A258863 A258864 A258865

KEYWORD

nonn

AUTHOR

Alois P. Heinz, Jun 12 2015

STATUS

approved

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Last modified October 18 05:31 EDT 2019. Contains 328146 sequences. (Running on oeis4.)