A371034 For n >= 1, a(n) = A004086(n) if A055483(n) = 1, otherwise a(n) = n / A055483(n).

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 4, 31, 41, 5, 61, 71, 2, 91, 10, 7, 1, 32, 4, 52, 13, 3, 14, 92, 10, 13, 23, 1, 43, 53, 4, 73, 83, 13, 10, 14, 7, 34, 1, 5, 23, 74, 4, 94, 10, 17, 25, 35, 6, 1, 65, 19, 85, 95, 10, 16, 31, 7, 32, 56, 1, 76, 34, 23, 10, 17, 8, 37, 47

Offset

1,12

Comments

Also a(n) = R(n) if (n, R(n)) are coprime, otherwise a(n) = n / GCD(n, R(n)), where R(n) is the digit reversal of n. a(n) = 1 for n from the union of A011557 and A002113 and A001232 and A008918.

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Formula

a(A011557(k)) = 1, k >= 0.

a(A002113(k)) = 1, k >= 2.

a(A001232(k)) = 1, k >= 1.

a(A008918(k)) = 1, k >= 1.

Example

n = 13: A004086(13) = 31, A055483(13) = 1 thus a(13) = 31.
n = 15: A004086(15) = 51, A055483(15) = 3 thus a(15) = 15/3 = 5.

Maple

rev:= proc(n) local L, i;
  L:= convert(n, base, 10);
  add(L[-i]*10^(i-1), i=1..nops(L))
end proc:
f:= proc(n) local r, g;
  r:= rev(n);
  g:= igcd(n, r);
  if g = 1 then r else n/g fi
end proc;
map(f, [$1..100]); # Robert Israel, Jul 09 2024

Mathematica

a[n_] := Module[{r = IntegerReverse[n], g}, g = GCD[n, r]; If[g == 1, r, n/g]]; Array[a, 100] (* Amiram Eldar, Mar 31 2024 *)

Crossrefs

Cf. A001232, A002113, A002275, A004086, A008918, A011557, A055483, A306273.

Sequence in context: A345274 A025416 A043082 * A216302 A070522 A087689

Adjacent sequences: A371031 A371032 A371033 * A371035 A371036 A371037

Keyword

nonn,base,look

Author

Ctibor O. Zizka, Mar 31 2024

Status

approved