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 A123269 Sum[ i^j^k, {i,1,n}, {j,1,n}, {k,1,n} ]. 2
 1, 28, 7625731729896, 13407807929942597099574024998205985135931742965325158317510351105024878248924471298029103219186757034747676158536830429928105045387310278568778808509188348 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS The next term is too large to include. Prime p divides a(p) for p = {2, 3, 7, 11, 23, 31, 43, 47, 59, 67, 71, 79, ...} = A039787[n] Primes p such that p-1 is squarefree. p^2 divides a(p) for prime p = {2,3}. LINKS FORMULA a(n) = Sum[ i^j^k, {i,1,n}, {j,1,n}, {k,1,n} ]. MATHEMATICA Table[Sum[i^j^k, {i, 1, n}, {j, 1, n}, {k, 1, n}], {n, 1, 5}] PROG (PARI) a(n)=sum(i=1, n, sum(j=1, n, sum(k=1, n, i^j^k))) \\ Charles R Greathouse IV, May 15 2013 CROSSREFS Cf. A039787. Cf. A086787 - Sum[ i^j, {i, 1, n}, {j, 1, n} ]. Numbers n that divide a(n) are listed in A124391(n) = {1, 2, 3, 4, 6, 7, 8, 9, 11, 12, 14, 16, 18, 20, 21, 22, 23, 24, 27, 28, 31, ...}. Sequence in context: A234620 A137942 A099090 * A067158 A243001 A092995 Adjacent sequences:  A123266 A123267 A123268 * A123270 A123271 A123272 KEYWORD nonn AUTHOR Alexander Adamchuk, Oct 09 2006 STATUS approved

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Last modified September 19 12:57 EDT 2019. Contains 327198 sequences. (Running on oeis4.)