1,5

Partial sums of number of positive knots with n crossings. The subsequence of distinct primes in this partial sum begins: 2, 3, 5, 17, 43.

Table of n, a(n) for n=1..15.

Index entries for sequences related to knots

a(n) = SUM[i=1..n] A018891(i).

a(15) = 0 + 0 + 1 + 0 + 1 + 0 + 1 + 1 + 1 + 3 + 2 + 7 + 9 + 17 + 47 = 90.

Cf. A018891.

Sequence in context: A228693 A116676 A240575 * A285261 A100483 A182613

Adjacent sequences: A176535 A176536 A176537 * A176539 A176540 A176541

nonn

Jonathan Vos Post, Apr 19 2010

approved