A302801 a(n) is the number whose digits result from the concatenation of the digits of n and the digits of the product of the digits of n.

0, 11, 22, 33, 44, 55, 66, 77, 88, 99, 100, 111, 122, 133, 144, 155, 166, 177, 188, 199, 200, 212, 224, 236, 248, 2510, 2612, 2714, 2816, 2918, 300, 313, 326, 339, 3412, 3515, 3618, 3721, 3824, 3927, 400, 414, 428, 4312, 4416, 4520, 4624, 4728, 4832, 4936, 500, 515

Offset

0,2

Links

Table of n, a(n) for n=0..51.

Altug Alkan, Line graph of first differences of a(n) for n <= 10^5

Example

For n=10, the digits of n are 1 and 0, their product is 0, and the concatenation gives 1 0 0.

Mathematica

Table[FromDigits[Join[IntegerDigits[n], IntegerDigits[Product[Part[IntegerDigits[n], k], {k, Length[IntegerDigits[n]]}]]]], {n, 0, 51}] (* Stefano Spezia, Aug 13 2023 *)

Prog

(PARI) mydigits(n) = if (n, digits(n), [0]);
a(n) = my(d = mydigits(n)); fromdigits(concat(d, mydigits(prod(k=1, #d, d[k]))));

Crossrefs

Cf. A007954, A108773, A302575.

Sequence in context: A276769 A160861 A302575 * A067042 A078273 A345391

Adjacent sequences: A302798 A302799 A302800 * A302802 A302803 A302804

Keyword

nonn,base,easy

Author

Michel Marcus, Apr 13 2018

Status

approved