A084970 Numbers whose smallest prime factor is 13.

13, 169, 221, 247, 299, 377, 403, 481, 533, 559, 611, 689, 767, 793, 871, 923, 949, 1027, 1079, 1157, 1261, 1313, 1339, 1391, 1417, 1469, 1651, 1703, 1781, 1807, 1937, 1963, 2041, 2119, 2171, 2197, 2249, 2327, 2353, 2483, 2509, 2561, 2587, 2743, 2873

Offset

1,1

Links

Amiram Eldar, Table of n, a(n) for n = 1..10000

Index entries for linear recurrences with constant coefficients, order 481.

Formula

a(n) = a(n-480) + 30030 = a(n-1) + a(n-480) - a(n-481). - Charles R Greathouse IV, Nov 19 2014

Lim_{n->infinity} a(n)/n = A038111(6)/A038110(6) = 1001/16 = 62.5625. - Vladimir Shevelev, Jan 20 2015

a(n) = 13*A008365(n).

Example

a(2) = 13*13, a(3) = 13*17.

Mathematica

Select[ 13Range@ 225, GCD[#, 2310] == 1 &] (* Robert G. Wilson v, Dec 18 2014 *)

Prog

(PARI) is(n)=n%13==0 && gcd(n, 2310)==1 \\ Charles R Greathouse IV, Nov 19 2014

Crossrefs

Sixth row of A083140.

Cf. A084967 (5), A084968 (7), A084969 (11), A332799 (17), A332798 (19), A332797 (23), A008365 (13-rough numbers).

Sequence in context: A171318 A078362 A157381 * A209226 A208503 A207696

Adjacent sequences: A084967 A084968 A084969 * A084971 A084972 A084973

Keyword

nonn,easy

Author

Robert G. Wilson v, Jun 15 2003

Extensions

More terms from David Wasserman, Oct 19 2004

Status

approved