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A263541 Numbers k such that k divides the sum of the first k primes with prime indices. 2
1, 2, 4, 6, 40, 43, 705, 789, 1148, 2140, 4276, 5512, 6672, 8754, 38434, 174501, 493578, 598249, 628064, 702774, 1368196, 4584004, 13813057, 36425906, 87964443, 447997476, 1964288296 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
There are 8 values of a(n) < 1000 although A045345 has 4 values A045345(n) < 1000. How do these sequences compare asymptotically?
Heuristics suggest that the ratio of the number of terms in each sequence up to x should approach 1 as x increases without bound. In the Cramér model, log a(n) and log A045345(n) are Erlang-distributed with shape n and rate 1. - Charles R Greathouse IV, Oct 20 2015
LINKS
EXAMPLE
1 is in the sequence because prime(prime(1)) = 3 is divisible by 1.
2 is in the sequence because prime(prime(1)) + prime(prime(2)) = 3 + 5 = 8 is divisible by 2.
PROG
(PARI) list(lim)=my(v=List(), k, s, t); forprime(p=2, , if(isprime(t++), s+=p; k++; if(s%k==0, listput(v, k)); if(k>=lim, return(Vec(v))))) \\ Charles R Greathouse IV, Oct 20 2015
CROSSREFS
Sequence in context: A175877 A269265 A173818 * A283157 A344422 A084324
KEYWORD
nonn
AUTHOR
Altug Alkan, Oct 20 2015
EXTENSIONS
a(12)-a(26) from Charles R Greathouse IV, Oct 20 2015
a(27) from Charles R Greathouse IV, Oct 21 2015
STATUS
approved

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Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)