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A338928
Record values of A338565.
0
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
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
Sequence in context: A068194 A375283 A179985 * A110705 A139439 A376735
KEYWORD
nonn
AUTHOR
Robert Israel, Nov 15 2020
STATUS
approved