|
|
A221745
|
|
Integer solutions to n^4 = x^3 + y^2 (values of y sorted by n).
|
|
1
|
|
|
3, 29, 76, 397, 433, 4785, 6083, 175784, 32507, 143027, 4146689, 4308693, 298483, 648613, 474554340, 7079295, 3085855, 30042907, 3881837, 8288063, 5692856, 5734653, 7790076, 8893220, 128277120493, 22015007, 374524445203, 49060477, 54142096, 109233295, 63051523, 22454830331, 444716637, 101907569, 105952427, 169483859, 169792053, 949475843, 2882277973, 1282239885136, 353814916, 395856397, 100314399, 655054991, 14549866883, 579133627, 433336175, 1177246693
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
LINKS
|
|
|
EXAMPLE
|
433 is in the sequence since we have 42^4 = 143^3 + 433^2.
|
|
MATHEMATICA
|
(* Same program as A096741 except the final selection : *) nmax = 25000; r[{n_, x_}] := (rn = Reduce[x != 0 && y > 0 && GCD[n, x, y] == 1 && n^4 == x^3 + y^2, y, Integers]; If[rn =!= False, {n, x, y} /. ToRules[rn], {0, 0, 0}]); tab = Table[ r@{a[k][s, t] // Abs, -b[k][s, t]}, {k, 1, 7}, {s, -5, 8}, {t, 0, 5}] // Flatten[#, 2] & // Select[#, 0 < #[[1]] < nmax &] & // Union; Select[tab, # != {0, 0, 0} &][[All, 3]]
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|