A085267 Numbers having at least two representations as sum of a squarefree number and a nonzero square.

6, 7, 10, 11, 12, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78

Offset: 1

Author

Reinhard Zumkeller, Jun 23 2003

Keywords

• nonn

Comments

Numbers n such that A085263(a(n)) > 1.

Conjecture: for n > 50, a(n) = n + 11. - Charles R Greathouse IV, Oct 26 2011

Links

• Eric Weisstein's World of Mathematics, Square Number
• Eric Weisstein's World of Mathematics, Squarefree

Crossrefs

Cf. A085265, A085266.

Programs

PARI

is(n)=my(t);forstep(k=sqrtint(n-1),1,-1,if(issquarefree(n-k^2),if(t++>1,return(1))));0 \\ Charles R Greathouse IV, Mar 12 2012