A261072 Divisors of 1234567890987654321.

1, 3, 7, 9, 19, 21, 57, 63, 133, 171, 399, 1197, 928163, 2784489, 6497141, 8353467, 17635097, 19491423, 52905291, 58474269, 123445679, 158715873, 370337037, 1111011111, 1111211111, 3333633333, 7778477777, 10000899999, 21113011109

Offset

1,2

Comments

1234567890987654321 = A057139(10) is a palindrome with 48 divisors. See the link with all divisors.

From Wolfdieter Lang, Aug 22 2015: (Start)

The palindromes of this sequence are 1, 3, 7, 9, 171, 1234567890987654321.

1234567890987654321 = 1111011111 * 1111211111 (observed by Jon E. Schoenfield).

The palindromic divisors of 1111011111 are 1, 3, 7, 9 and 171. The only palindromic divisor of 1111211111 is 1. Therefore, of the six palindromes of this sequence only 1234567890987654321 cannot be obtained from the product of the palindromic divisors of 1111011111 with those of 1111211111. (End)

Links

Ilya Gutkovskiy, Table of n, a(n) for n = 1..48

Eric Weisstein's World of Mathematics, Divisor.

Eric Weisstein's World of Mathematics, Palindromic Number.

Maple

numtheory[divisors](1234567890987654321); # Wesley Ivan Hurt, Aug 11 2015

Mathematica

Divisors[1234567890987654321]

Prog

(Magma) [Divisors(1234567890987654321)]; // Vincenzo Librandi, Aug 09 2015
(PARI) divisors(1234567890987654321) \\ Wesley Ivan Hurt, Aug 11 2015

Crossrefs

Cf. A057139, A261245.

Sequence in context: A003528 A032913 A353397 * A154508 A073573 A309328

Adjacent sequences: A261069 A261070 A261071 * A261073 A261074 A261075

Keyword

nonn,easy,fini,full

Author

Ilya Gutkovskiy, Aug 08 2015

Status

approved