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A335859 Terms of A334245 in increasing order and without repetition. 2
12, 15, 21, 30, 35, 57, 60, 65, 70, 77, 91, 105, 111, 114, 119, 126, 133, 143, 147, 150, 155, 165, 168, 180, 185, 190, 198, 209, 217, 220, 231, 234, 255, 260, 264, 294, 301, 310, 312, 319, 323, 330, 341, 360, 427, 432, 437, 455, 456, 462, 473, 497, 504, 510, 511, 546, 559, 588 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

See the network with the 50 smallest merging points of A334245 in link.

LINKS

Robert Israel, Table of n, a(n) for n = 1..5939

Bernard Schott and Blandine Schott, Network of merging points.

EXAMPLE

l means: add least prime factor, and,

L means: add largest prime factor.

For 3:

   L:  3 + 3 = 6            l: 3 + 3 = 6

   l:  6 + 2 = 8            L: 6 + 3 = 9

   L:  8 + 2 = 10           l: 9 + 3 = 12

   l: 10 + 2 = 12

So A334245(3) = 12 and 12 is a merging point with a(1) = 12.

Now, for 12:

   L: 12 + 3 = 15           l: 12 + 2 = 14

   l: 15 + 3 = 18           L: 14 + 7 = 21

   L: 18 + 3 = 21

So A334245(12) = 21 and 21 is the merging point corresponding to 12 with a(3) = 21.

MAPLE

N:= 1000: # to get all values <= N

S:= x -> x + min(numtheory:-factorset(x)):

T:= x -> x + max(numtheory:-factorset(x)):

f:= proc(n) g(S(n), T(n), 0, 1) end proc:

g:= proc(s, t, i, j) option remember;

      if max(s, t) > N then return 0 fi;

      if s = t and i=j then return s fi;

      if s <= t then

        if i = 0 then procname(T(s), t, 1, j)

        else procname(S(s), t, 0, j)

        fi

      elif j=0 then procname(s, T(t), i, 1)

      else procname(s, S(t), i, 0)

      fi

end proc:

sort(convert(map(f, {$2..N}) minus {0}, list)); # Robert Israel, Jul 09 2020

CROSSREFS

Cf. A334245.

Sequence in context: A162826 A162820 A267195 * A259040 A158190 A122040

Adjacent sequences:  A335856 A335857 A335858 * A335860 A335861 A335862

KEYWORD

nonn

AUTHOR

Bernard Schott, Jun 27 2020

STATUS

approved

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Last modified August 3 06:43 EDT 2021. Contains 346435 sequences. (Running on oeis4.)