A049632 a(n) = T(n,n), array T as in A049627.

1, 4, 6, 10, 14, 22, 26, 38, 46, 58, 66, 86, 94, 118, 130, 146, 162, 194, 206, 242, 258, 282, 302, 346, 362, 402, 426, 462, 486, 542, 558, 618, 650, 690, 722, 770, 794, 866, 902, 950, 982, 1062, 1086, 1170, 1210, 1258, 1302, 1394, 1426, 1510, 1550, 1614, 1662

Offset

0,2

Links

Table of n, a(n) for n=0..52.

Formula

a(n) = 2*A005728(n) if n>=1. - R. J. Mathar, Feb 05 2008

Prog

(PARI) T(n, k) = (n+1)*(k+1) - sum(i=0, n, sum(j=0, k, gcd(i, j)>1)); \\ A049627
a(n) = T(n, n); \\ Michel Marcus, Aug 06 2021

Crossrefs

Cf. A049627, A049643, A005728.

Sequence in context: A076924 A103801 A141247 * A216732 A276983 A061227

Adjacent sequences: A049629 A049630 A049631 * A049633 A049634 A049635

Keyword

nonn

Author

Clark Kimberling

Extensions

More terms from Sean A. Irvine, Aug 05 2021

Status

approved