A338928 Record values of A338565.

1, 2, 3, 4, 7, 17, 21, 38, 58, 82, 148, 174, 176, 360, 362, 479, 846, 1289, 1934, 2196, 3315, 4326, 5701, 8225, 8910, 9507, 11346, 14262, 19832, 25072, 30279, 34638, 46714, 67520, 78082, 82112, 94916, 107902, 175532, 195760, 273164, 275892, 443284, 479324

Offset

1,2

Links

Table of n, a(n) for n=1..44.

Formula

a(n) = A338565(A338927(n)).

Maple

ispali:= proc(n) local L;
  L:= convert(n, base, 10);
  evalb(L = ListTools:-Reverse(L))
end proc:
N:= 200000: # for terms <= N
Palis:= select(ispali, {$2..N}):
A338565:= Vector(N):
A338565[1]:= 1:
R:= 1: bestv:= 1:
A[1]:= 1:
for n from 2 to N do
  A[n]:=  add(A[n/d], d= numtheory:-divisors(n) intersect Palis);
    if A[n] > bestv then bestv:= A[n]; R:= R, bestv
od:
R;

Mathematica

Block[{a}, a[n_] := If[n == 1, n, Sum[If[(d < n && PalindromeQ[n/d]), a[d], 0], {d, Divisors[n]}]]; Union@ FoldList[Max, Array[a, 10^4]]] (* Michael De Vlieger, Nov 15 2020 *)

Crossrefs

Cf. A338565, A338927.

Sequence in context: A027362 A068194 A179985 * A110705 A139439 A352902

Adjacent sequences: A338925 A338926 A338927 * A338929 A338930 A338931

Keyword

nonn

Author

Robert Israel, Nov 15 2020

Status

approved