The OEIS is supported by the many generous donors to the OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A199997 Composite numbers whose multiplicative persistence is 7. 0
 68889, 68898, 68988, 69888, 86889, 86898, 86988, 88689, 88698, 88869, 88896, 88968, 88986, 89688, 89868, 89886, 96888, 98688, 98868, 98886, 168889, 168898, 168988, 169888, 186898, 186988, 188689, 188698, 188896, 188968, 188986, 189688, 189868, 189886, 196888 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Complement of A046507 with respect to A046516. LINKS Table of n, a(n) for n=1..35. EXAMPLE 68889 -> [ 27648 ][ 2688 ][ 768 ][ 336 ][ 54 ][ 20 ][ 0 ] -> one digit in seven steps. MATHEMATICA persistence[n_] := Module[{cnt = 0, k = n}, While[k > 9, cnt++; k = Times @@ IntegerDigits[k]]; cnt]; Select[Range[300000], ! PrimeQ[#] && persistence[#] == 7 &] (* T. D. Noe, Nov 23 2011 *) CROSSREFS Cf. A046507 (primes whose multiplicative persistence is 7). Sequence in context: A233721 A121107 A046516 * A250500 A354194 A096551 Adjacent sequences: A199994 A199995 A199996 * A199998 A199999 A200000 KEYWORD nonn,base AUTHOR Jaroslav Krizek, Nov 13 2011 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified April 21 19:03 EDT 2024. Contains 371874 sequences. (Running on oeis4.)