OFFSET
1,1
COMMENTS
225, 1050, 1176, 2028, 3025, 6075, 7260, 8400, 8450, 8820, 9408, 10890, 12312, 18375, 19494, 21160, 24696, 26775, 28125, 28350, 31752, 31974, 34300, 39600, 43245, 44100, 49923, 53361, 54756, 58080, 64980, 67200, 71415, 75264, 87120, 98496, 131250, 139425, 144150, 145656, 159048, 164025, ... have three solutions;
1800, 11025, 14400, 16224, 38025, 48600, 61347, 67600, 70560, 81675, 88200, 115200, 129792, 147000, 155952, 166419, ... have four solutions;
24200, 77175, ... have five solutions.
A242192(a(n)) > 1. - Reinhard Zumkeller, May 07 2014
LINKS
Lars Blomberg, Table of n, a(n) for n = 1..202
EXAMPLE
72 is in the sequence since 72^4 = 1728^2 + 288^3 = 4941^2 + 135^3.
MATHEMATICA
f[n_] := f[n] = Module[{a}, Array[(a = Sqrt[n^4 - #^3]; If[ IntegerQ@ a && a > 0, {a, #}, Sequence @@ {}]) &, Floor[n^(4/3)]]]; Select[ Range@ 10000, f@# > 1 &]
PROG
(Haskell)
a242186 n = a242186_list !! (n-1)
a242186_list = filter ((> 1) . a242192) [1..]
-- Reinhard Zumkeller, May 07 2014
CROSSREFS
KEYWORD
nonn
AUTHOR
Lars Blomberg and Robert G. Wilson v, May 06 2014
STATUS
approved