A204998 a(n) = k^2 - j^2, where (k^2,j^2) is the least pair of distinct squares for which n divides their difference.

3, 8, 3, 8, 5, 12, 7, 8, 9, 20, 11, 12, 13, 28, 15, 16, 17, 72, 19, 20, 21, 44, 23, 24, 75, 52, 27, 28, 29, 60, 31, 32, 33, 68, 35, 72, 37, 76, 39, 40, 41, 84, 43, 44, 45, 92, 47, 48, 147, 200, 51, 52, 53, 108, 55, 56, 57, 116, 59, 60, 61, 124, 63, 64, 65, 132, 67, 68, 69, 140, 71, 72, 73, 148, 75, 76, 77, 156, 79, 80, 81, 164

Offset

1,1

Comments

For a guide to related sequences, see A204892.

Links

Antti Karttunen, Table of n, a(n) for n = 1..23005

Formula

a(n) = A204996(n) - A204997(n).

Mathematica

(See the program at A204994.)

Prog

(PARI) A204998(n) = { my(d); for(k=sqrtint(1+n), oo, for(j=1, k-1, if(!((d=(k^2)-(j^2))%n), return(d), if(d<n, break)))); }; \\ Antti Karttunen, Sep 28 2018

Crossrefs

Cf. A204994, A204892, A204996, A204997, A204999.

Sequence in context: A125025 A309345 A010706 * A019919 A213277 A135608

Adjacent sequences: A204995 A204996 A204997 * A204999 A205000 A205001

Keyword

nonn

Author

Clark Kimberling, Jan 21 2012

Extensions

More terms from Antti Karttunen, Sep 28 2018

Status

approved