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A034708 Numbers for which the sum of reciprocals of digits is an integer. 9
1, 11, 22, 111, 122, 212, 221, 236, 244, 263, 326, 333, 362, 424, 442, 623, 632, 1111, 1122, 1212, 1221, 1236, 1244, 1263, 1326, 1333, 1362, 1424, 1442, 1623, 1632, 2112, 2121, 2136, 2144, 2163, 2211, 2222, 2316, 2361, 2414, 2441, 2488, 2613, 2631, 2666 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Intersection of A214957 and A052382: A214950(a(n))*A168046(a(n)) = 1. - Reinhard Zumkeller, Aug 02 2012

LINKS

Reinhard Zumkeller, Table of n, a(n) for n = 1..1000

MATHEMATICA

f[ n_ ] := 1/n a[ n_ ] := Apply[ Plus, Map[ f, IntegerDigits[ n ] ] ] Select[ Range[ 1000 ], FreeQ[ IntegerDigits[ # ], 0 ] && IntegerQ[ a [ # ] ] & ] (* Santi Spadaro, Oct 13 2001 *)

Select[Range[3000], DigitCount[#, 10, 0]==0 && IntegerQ[Total[ 1/IntegerDigits[#]]]&] (* Harvey P. Dale, May 06 2012 *)

PROG

(Haskell)

a034708 n = a034708_list !! (n-1)

a034708_list = filter ((== 1) . a168046) a214957_list

-- Reinhard Zumkeller, Aug 02 2012

(PARI) isok(n) = {my(d = digits(n)); vecmin(d) && denominator(sum(k=1, #d, 1/d[k])) == 1; } \\ Michel Marcus, Feb 12 2016

CROSSREFS

Sequence in context: A047902 A081930 A143964 * A091784 A213972 A061852

Adjacent sequences:  A034705 A034706 A034707 * A034709 A034710 A034711

KEYWORD

nonn,base,nice

AUTHOR

Erich Friedman

STATUS

approved

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Last modified June 24 08:22 EDT 2017. Contains 288697 sequences.