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A062179 Harmonic mean of digits is an integer. 8
1, 2, 3, 4, 5, 6, 7, 8, 9, 11, 22, 26, 33, 36, 44, 55, 62, 63, 66, 77, 88, 99, 111, 136, 144, 163, 222, 236, 244, 263, 288, 316, 326, 333, 346, 361, 362, 364, 414, 424, 436, 441, 442, 444, 463, 488, 555, 613, 623, 631, 632, 634, 643, 666, 777, 828, 848, 882, 884 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Harvey P. Dale, Table of n, a(n) for n = 1..1000

EXAMPLE

1236 is a term as the harmonic mean is 4/(1+1/2+1/3+1/6) = 2.

MATHEMATICA

Do[ h = IntegerDigits[n]; If[ Sort[h] [[1]] != 0 && IntegerQ[ Length[h] / Apply[ Plus, 1/h] ], Print[n]], {n, 1, 10^4} ] Note that the number of entries <= 10^n are 9, 22, 61, 198, 927, 4738, 24620, 130093,

hmdiQ[n_]:=DigitCount[n, 10, 0]==0&&IntegerQ[HarmonicMean[ IntegerDigits[ n]]]; Select[Range[1000], hmdiQ] (* Harvey P. Dale, Sep 22 2012 *)

CROSSREFS

Cf. A062180-A062185, A061383-A061388, A061423-A061425.

Sequence in context: A107272 A039228 A161383 * A122875 A080716 A166461

Adjacent sequences:  A062176 A062177 A062178 * A062180 A062181 A062182

KEYWORD

base,easy,nonn

AUTHOR

Vladeta Jovovic, Jun 12 2001

EXTENSIONS

More terms from Robert G. Wilson v, Aug 08 2001

STATUS

approved

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Last modified June 26 10:01 EDT 2022. Contains 354879 sequences. (Running on oeis4.)