

A172151


Number of partitions of n into two nonsquares.


6



0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 2, 3, 4, 4, 4, 5, 5, 5, 5, 7, 6, 7, 7, 8, 9, 9, 8, 9, 10, 10, 10, 11, 11, 13, 12, 13, 13, 13, 13, 15, 15, 15, 15, 16, 17, 17, 17, 18, 18, 19, 18, 20, 20, 20, 20, 21, 21, 23, 22, 23, 24, 24, 24, 25, 26, 25, 25, 27, 26, 27, 27, 28, 29, 30, 29, 30, 30, 31
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OFFSET

0,9


COMMENTS

A172152 and A172153 give record values and where they occur: a(A172153(n))=A172152(n) and a(m) < A172152(n) for m < A172153(n).


LINKS

R. Zumkeller, Table of n, a(n) for n = 0..10000


FORMULA

a(n) = n/2 + O(sqrt(n)).  Charles R Greathouse IV, Aug 28 2016


EXAMPLE

a(8) = #{6+2, 5+3} = 2;
a(9) = #{7+2, 6+3} = 2;
a(10) = #{8+2, 7+3, 5+5} = 3;
a(11) = #{8+3, 6+5} = 2;
a(12) = #{10+2, 7+5, 6+6} = 3;
a(13) = #{11+2, 10+3, 8+5, 7+6} = 4.


PROG

(PARI) a(n)=n\2  sqrtint(n) + sum(k=sqrtint(n\2)+1, sqrtint(n), issquare(nk^2)) \\ Charles R Greathouse IV, Aug 28 2016


CROSSREFS

Cf. A000037, A004526, A087153.
Sequence in context: A271914 A087735 A277194 * A106250 A029248 A085916
Adjacent sequences: A172148 A172149 A172150 * A172152 A172153 A172154


KEYWORD

nonn,easy


AUTHOR

Reinhard Zumkeller, Jan 26 2010


EXTENSIONS

Typo in bfile link fixed by Reinhard Zumkeller, Feb 10 2010


STATUS

approved



