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URL: https://oeis.org/A054402

⇱ A054402 - OEIS

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A054402
Numbers that are the sum of a positive square and a positive cube in more than one way.
7
17, 65, 89, 108, 129, 145, 225, 233, 252, 297, 316, 388, 449, 464, 505, 537, 548, 577, 593, 633, 730, 737, 745, 792, 793, 801, 873, 1025, 1088, 1090, 1116, 1289, 1304, 1305, 1367, 1412, 1441, 1452, 1529, 1585, 1601
OFFSET
1,1
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..10000
EXAMPLE
a(1)=17 since 17 = 3^2 + 2^3 = 4^2 + 1^3.
MATHEMATICA
lst={}; Do[Do[AppendTo[lst, n^2+m^3], {n, 5!}], {m, 5!}]; lst=Sort[lst]; lst2={}; Do[If[lst[[n]]==lst[[n+1]], AppendTo[lst2, lst[[n]]]], {n, Length[lst]-1}]; lst2; Take[Union[lst2], 123] (* Vladimir Joseph Stephan Orlovsky, Jul 17 2009 *)
PROG
(PARI) list(lim)=my(v=List(), u=List()); for(n=1, sqrtint(lim\1-1), for(m=1, sqrtnint(lim\1-n^2, 3), listput(v, n^2+m^3))); v=vecsort(v); for(i=2, #v, if(v[i]==v[i-1], listput(u, v[i]))); Set(u) \\ Charles R Greathouse IV, May 15 2015
CROSSREFS
Sequence in context: A145850 A125992 A363714 * A086533 A226685 A108211
KEYWORD
easy,nonn
AUTHOR
Henry Bottomley, May 12 2000
STATUS
approved