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A257275 Numbers equal to some partial product of the sequence of their digits, repeated over and over again. 1
1, 2, 3, 4, 5, 6, 7, 8, 9, 735, 18432, 442368, 3682784876146817236992 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

The sequence is conjectured to be finite (D. Wilson, Reply on the SeqFan list).

There are no additional terms below 10^300. - Max Alekseyev, Apr 29 2015

LINKS

Table of n, a(n) for n=1..13.

E. Angelini (and replies by H. P. Dale and D. Wilson), Cumulative multiplication, April 18, 2015

C. Meller, 1392 - Producto acumulado, April 21, 2015.

C. Rivera, Puzzle 784: Find some more solutions, April 25, 2015

EXAMPLE

735 = 7 * 3 * 5 * 7

18432 = 1 * 8 * 4 * 3 * 2 * 1 * 8 * 4 * 3

442368 = 4 * 4 * 2 * 3 * 6 * 8 * 4 * 4 * 2 * 3

3682784876146817236992 = A007954(3682784876146817236992) * A007954(3682784876). - Giovanni Resta, Apr 29 2015.

MATHEMATICA

Select[Range[450000], MemberQ[FoldList[Times, PadRight[{}, 50, IntegerDigits[#]]], #]&] (* The program will generate the first 12 terms of the sequence. *) (* Harvey P. Dale, Jun 21 2017 *)

PROG

(PARI) is(n, d=digits(n), p=1)=for(i=0, n, (n>p*=d[i%#d+1])||return(n==p))

CROSSREFS

Subsequence of A007602 and likely of A128606 and A257554. - Max Alekseyev, Apr 29 2015

Sequence in context: A069747 A308126 A124107 * A112014 A145461 A075154

Adjacent sequences:  A257272 A257273 A257274 * A257276 A257277 A257278

KEYWORD

nonn,base,more

AUTHOR

M. F. Hasler, Apr 29 2015

EXTENSIONS

a(12) from Harvey P. Dale, Apr 18 2015

a(13) from Giovanni Resta, Apr 29 2015

STATUS

approved

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Last modified May 29 20:42 EDT 2020. Contains 334710 sequences. (Running on oeis4.)