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A245229 Primes that are the sum of 7 cubes and no fewer. 0
7, 47, 61, 103, 113, 211, 223, 229, 311, 337, 401, 419, 491, 787, 1021, 1453, 1489, 1697, 2039, 3659, 4703, 5279 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Intersection of A018890 and A000040.

If, as is conjectured, the last term of A018890 is 8042, there are no more terms than those shown. - Robert Israel, Jul 14 2014

LINKS

Table of n, a(n) for n=1..22.

EXAMPLE

a(1) = 7 = 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3 + 1^3.

a(2) = 47 = 3^3 + 2^3 + 2^3 + 1^3 + 1^3 + 1^3 + 1^3.

a(3) = 61 = 3^3 + 2^3 + 2^3 + 2^3 + 2^3 + 1^3 + 1^3.

a(4) = 103 = 4^3 + 3^3 + 2^3 + 1^3 + 1^3 + 1^3 + 1^3.

MAPLE

for n from 1 to 10^4 do

  m:= floor(n^(1/3));

  if m^3 = n then M[n]:= 1

  else

    M[n]:= 1 + min(seq(M[n-j^3], j=1..m));

  fi

od:

select(n -> M[n]=7 and isprime(n), [$1..10^4]); # Robert Israel, Jul 14 2014

CROSSREFS

Cf. A000578, A018890, A000040.

Sequence in context: A124837 A122731 A059452 * A141882 A240569 A261183

Adjacent sequences:  A245226 A245227 A245228 * A245230 A245231 A245232

KEYWORD

nonn,less,fini

AUTHOR

Rafael F. Farias, Jul 13 2014

STATUS

approved

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Last modified April 21 01:03 EDT 2019. Contains 322310 sequences. (Running on oeis4.)