A166088 Odd integers (that is, of the form 2n+1) for which Sum_{i=1..u} J(i,2n+1) obtains value zero exactly 8 times, when u ranges from 1 to (2n+1). Here J(i,k) is the Jacobi symbol.

29, 37, 41, 65, 73, 97, 177, 193

Offset

1,1

Comments

Of these eight, all are of the form 4k+1, and all others are primes except 65 (= 5*13) and 177 (= 3*59). Conjecture: There are no more terms after the eight one, 193. (Checked up to the 400000th term of A166040, i.e., up to A005408(400000)=800001.)

Links

Table of n, a(n) for n=1..8.

Prog

(MIT/GNU Scheme)
; with macro MATCHING-POS by AK
(define (A166088 n) (A005408 (index_for_a166088 n)))
(define index_for_a166088 (MATCHING-POS 1 0 (lambda (i) (= 8 (A166040 i)))))

Crossrefs

Sequence in context: A250291 A127956 A347038 * A295490 A172195 A161724

Adjacent sequences: A166085 A166086 A166087 * A166089 A166090 A166091

Keyword

nonn

Author

Antti Karttunen, Oct 08 2009

Status

approved