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A037264 Numbers whose sum of reciprocals of digits is the 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
63 is a term: 1/((1/6) + (1/3)) = 2.
MATHEMATICA
Reap[Do[If[FreeQ[id = IntegerDigits[n], 0], If[IntegerQ[1/Total[1/id]], Sow[n]]], {n, 1, 10^4}]][[2, 1]] (* Jean-François 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
(Python)
from fractions import Fraction
def ok(n):
ds = list(map(int, str(n)))
return 0 not in ds and sum(Fraction(1, d) for d in ds).numerator == 1
print(list(filter(ok, range(1, 6337)))) # Michael S. Branicky, Aug 08 2021
CROSSREFS
Sequence in context: A083158 A254956 A061013 * A274124 A045910 A128290
KEYWORD
easy,nonn,nice,base,fini,full
AUTHOR
STATUS
approved

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Last modified April 23 02:53 EDT 2024. Contains 371906 sequences. (Running on oeis4.)