A173517 a(n) = k if n is the k-th nonsquare, zero otherwise.

0, 0, 1, 2, 0, 3, 4, 5, 6, 0, 7, 8, 9, 10, 11, 12, 0, 13, 14, 15, 16, 17, 18, 19, 20, 0, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 0, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 0, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 0, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67

Offset: 0

Author

Reinhard Zumkeller, Feb 20 2010

Keywords

• nonn
• easy

Comments

a(A000037(n)) = n; a(A000290(n)) = 0.

a(n)*A037213(n) = 0 for all n.

Links

• Reinhard Zumkeller, Table of n, a(n) for n = 0..1000

Crossrefs

Cf. A000037, A000196, A000290, A010052, A028391, A037213.

Programs

Haskell

a173517 n = (1 - a010052 n) * a028391 n
-- Reinhard Zumkeller, Dec 15 2013

PARI

a(n)=if(issquare(n), 0, n-sqrtint(n)) \\ Charles R Greathouse IV, Sep 02 2015

Formula

a(n) = (1 - A010052(n))*A028391(n).

Extensions

Definition revised by Reinhard Zumkeller, Dec 15 2013, at the suggestion of Antti Karttunen, who further edited the name