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 A254324 Least Y such that X^3 + Y^3 = A020898(n)*Z^3 for some X <= Y and some Z. 2
 1, 37, 5, 2, 89, 7, 683 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 COMMENTS Also, max {X,Y,Z} for the smallest (in this sense of this sup norm) positive integer solution (X,Y,Z) to X^3 + Y^3 = A020898(n)*Z^3. The X values are given in A254326. a(8) > 10^5, with A020898(8)=17. Then the sequence continues a(9,10,...) = 5, 19, ?, 75, 3, 163, ?, 1853, ?, 3, 19, ... LINKS EXAMPLE A020898(1)=2 and 1^3 + 1^3 = 2*1^3, therefore a(1)=1. A020898(2)=6 and 17^3 + 37^3 = 6*21^3, and there is no "smaller" solution (with X, Y, Z < 37), therefore a(2)=37. PROG (PARI) a(n, L=10^9)={n=if(n>0, A020898[n], -n); for(b=1, L, for(a=1, b, (a^3+b^3)%n&&next; ispower((a^3+b^3)/n, 3)&&return(b)))} CROSSREFS Cf. A020898, A254326. Sequence in context: A278067 A178199 A107812 * A068843 A284497 A033357 Adjacent sequences:  A254321 A254322 A254323 * A254325 A254326 A254327 KEYWORD nonn,more AUTHOR M. F. Hasler, Jan 27 2015 STATUS approved

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Last modified May 14 16:48 EDT 2021. Contains 343898 sequences. (Running on oeis4.)