A199984 Composite numbers whose multiplicative digital root is 4.

4, 14, 22, 27, 39, 72, 93, 98, 114, 122, 141, 172, 189, 198, 212, 217, 221, 249, 266, 294, 319, 333, 338, 346, 364, 391, 411, 429, 436, 492, 626, 634, 662, 712, 721, 767, 772, 776, 793, 819, 833, 891, 913, 918, 924, 931, 942, 973, 981, 1114, 1122, 1127, 1139

Offset

1,1

Comments

Complement of A199983 with respect to A034051.

Links

Table of n, a(n) for n=1..53.

Example

Number 172 is in sequence because 1*7*2=14, 1*4=4.

Mathematica

cn4Q[n_]:=NestWhile[Times@@IntegerDigits[#]&, n, #>9&]==4; Select[Select[ Range[ 1200], CompositeQ], cn4Q] (* Harvey P. Dale, Apr 28 2018 *)

Crossrefs

Cf. A199983 (primes whose multiplicative digital root is 4).

Cf. A034051 (numbers whose multiplicative digital root is 4).

Sequence in context: A197638 A051806 A034051 * A044437 A298008 A279414

Adjacent sequences: A199981 A199982 A199983 * A199985 A199986 A199987

Keyword

nonn,base

Author

Jaroslav Krizek, Nov 13 2011

Status

approved