A227194 Natural numbers for which all sums Sum_{i=1..u} K(i/n) (with u ranging from 1 to n) are nonnegative, where K(i/n) is Kronecker symbol of i and n.

1, 2, 3, 4, 6, 7, 9, 10, 11, 12, 14, 15, 16, 23, 24, 25, 26, 27, 30, 31, 34, 35, 36, 38, 39, 42, 44, 47, 48, 49, 54, 55, 56, 58, 59, 62, 63, 64, 66, 71, 74, 75, 76, 79, 81, 82, 83, 86, 87, 94, 95, 96, 100, 103, 106, 108, 110, 111, 114, 119, 120, 121, 130, 131

Offset

1,2

Links

Table of n, a(n) for n=1..64.

Prog

(PARI) firstdiving(n) = {s=0; for(k=1, n, s=s+kronecker(k, n); if(s<0, return(k))); return(0)}
for(n=1, 500, if((0==firstdiving(n)), print1(n, ", ")))

Crossrefs

Subsets: A095100, A095102 (gives the prime terms). Cf. A227196-A227198.

Sequence in context: A051382 A026514 A285974 * A039054 A047519 A070118

Adjacent sequences: A227191 A227192 A227193 * A227195 A227196 A227197

Keyword

nonn

Author

Antti Karttunen, Jul 06 2013

Status

approved