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A037264 Numbers n such that sum of reciprocals of digits is reciprocal of an integer. 6
1, 2, 3, 4, 5, 6, 7, 8, 9, 22, 36, 44, 63, 66, 88, 236, 244, 263, 326, 333, 362, 424, 442, 488, 623, 632, 666, 848, 884, 999, 2488, 2666, 2848, 2884, 3366, 3446, 3464, 3636, 3644, 3663, 4288, 4346, 4364, 4436, 4444, 4463, 4634, 4643, 4828, 4882, 6266, 6336 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Intersection of A214958 and A052382: A214949(a(n))*A168046(a(n)) = 1. - Reinhard Zumkeller, Aug 02 2012

LINKS

T. D. Noe, Table of n, a(n) for n = 1..1232 (complete sequence)

EXAMPLE

E.g. 63: 1/((1/6)+(1/3)) = 2.

MAPLE

P:=proc(n) local a, b, k, ok; a:=convert(n, base, 10); b:=0; ok:=1;

for k from 1 to nops(a) do if a[k]>0 then b:=b+1/a[k]; else ok:=0;

break; fi; od; if ok=1 then if frac(1/b)=0 then n; fi; fi; end:

seq(P(i), i=1..6336); # Paolo P. Lava, May 24 2018

MATHEMATICA

Reap[Do[If[FreeQ[id = IntegerDigits[n], 0], If[IntegerQ[1/Total[1/id]], Sow[n]]], {n, 1, 10^4}]][[2, 1]] (* Jean-Fran├žois Alcover, Dec 15 2015 *)

PROG

(Haskell)

a037264 n = a037264_list !! (n-1)

a037264_list = filter ((== 1) . a168046) $

                      takeWhile (<= 999999999) a214958_list

-- Reinhard Zumkeller, Aug 02 2012

(PARI) isok(n) = {my(d=digits(n)); vecmin(d) && (numerator(sum(k=1, #d, 1/d[k])) == 1); } \\ Michel Marcus, May 24 2018

CROSSREFS

Cf. A037265, A045910.

Sequence in context: A083158 A254956 A061013 * A274124 A045910 A128290

Adjacent sequences:  A037261 A037262 A037263 * A037265 A037266 A037267

KEYWORD

easy,nonn,nice,base,fini,full

AUTHOR

Naohiro Nomoto

STATUS

approved

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Last modified March 23 09:20 EDT 2019. Contains 321424 sequences. (Running on oeis4.)