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A239685 Prime numbers for which the sum of reciprocals of nonzero digits equals 1. 0
263, 2063, 4463, 4643, 6203, 20063, 26003, 60443, 62003, 64403, 68483, 69929, 86843, 88463, 88643, 92699, 200063, 260003, 260999, 296099, 296909, 400643, 406403, 406883, 446003, 449699, 460403, 464003, 464999, 468803, 488603, 494699, 496499, 496949, 499649 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Primes in A214959.

Property of the sequence: a(n) == 3 or 9 (mod 10). If n contains nonzero digits, each number > 263 contains at least two identical digits, and the subsequence of the corresponding sum of reciprocals of digits (primes in A037268) is finite.

LINKS

Table of n, a(n) for n=1..35.

EXAMPLE

2063 is in the sequence because 1/2 + 1/6 + 1/3 = 1.

MAPLE

with(numtheory):nn:=500000:for m from 1 to nn do:n:=ithprime(m):y:=convert(n, base, 10):n2:=nops(y):s:=0:for i from 1 to n2 do: if y[i]<>0 then s:=s+1/y[i]:else fi:od:if s=1 then printf(`%d, `, n):else fi:od:

MATHEMATICA

Select[Prime[Range[42000]], Total[1/Select[IntegerDigits[#], #!=0&]]==1&] (* Harvey P. Dale, May 31 2019 *)

CROSSREFS

Cf. A037268, A214959.

Sequence in context: A343192 A023314 A054802 * A108823 A229480 A266036

Adjacent sequences:  A239682 A239683 A239684 * A239686 A239687 A239688

KEYWORD

nonn,base

AUTHOR

Michel Lagneau, Mar 24 2014

STATUS

approved

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Last modified July 3 10:25 EDT 2022. Contains 355050 sequences. (Running on oeis4.)