A103159 a(n) = GCD(reverse(n), reversed(n+1)).

1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 5, 5, 5, 5, 5, 5, 5, 5, 5, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 2, 2, 2, 2, 2, 2, 2, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1

Offset

1,20

Links

Alois P. Heinz, Table of n, a(n) for n = 1..10000

Formula

a(n) = GCD(A004086(n), A004086(n+1)).

Mathematica

rd[x_] :=FromDigits[Reverse[IntegerDigits[x]]] Table[GCD[rd[w], rd[w+1]], {w, 1, 100}]

Prog

(Python)
from math import gcd
def a(n): return gcd(int(str(n)[::-1]), int(str(n+1)[::-1]))
print([a(n) for n in range(1, 106)]) # Michael S. Branicky, Dec 12 2021

Crossrefs

Cf. A004086.

Sequence in context: A215887 A159451 A336682 * A063056 A174835 A297036

Adjacent sequences: A103156 A103157 A103158 * A103160 A103161 A103162

Keyword

base,nonn

Author

Labos Elemer, Jan 25 2005

Status

approved