

A275747


Largest integer which cannot be written as a sum of nth powers of odd primes.


3



4, 114, 1595, 24195, 190463, 4613167, 23815950, 240951477, 2448240688, 40379465440, 258630935725, 3044619003271, 26232953378021, 264066033166293, 3218396161633945, 29248021240625765, 302064442857973298, 3027736057187540859, 32207709908667683204
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OFFSET

1,1


COMMENTS

Except for n=6, only the powers of 3 primes are needed, namely 3^n, 5^n and 7^n, which leads to an ultrafast O(n) execution time. I executed the algorithm in Greenberg (1988) with a PARI/GP program in only a few seconds for 1000 terms.  Mike Oakes, Aug 16 2016


LINKS



EXAMPLE

For n=2, 114 is the largest integer which cannot be written as a sum of squares of odd primes.


MATHEMATICA

With[{prs=Prime[Range[2, 5]]}, Table[FrobeniusNumber[prs^n], {n, 20}]] (* Harvey P. Dale, Sep 19 2018 *)


CROSSREFS



KEYWORD

nonn


AUTHOR



STATUS

approved



