A077683 Squarefree numbers beginning with 7.

7, 70, 71, 73, 74, 77, 78, 79, 701, 703, 705, 706, 707, 709, 710, 713, 714, 715, 717, 718, 719, 721, 723, 727, 730, 731, 733, 734, 737, 739, 741, 742, 743, 745, 746, 749, 751, 753, 754, 755, 757, 758, 759, 761, 762, 763, 766, 767, 769, 770, 771, 773, 777, 778

Offset

1,1

Comments

Lower density is 3/(35*Pi^2), upper density is 5/(6*Pi^2). - Charles R Greathouse IV, Nov 05 2017

Links

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

Prog

(PARI) is(n)=n>6 && digits(n)[1]==7 && issquarefree(n) \\ Charles R Greathouse IV, Nov 05 2017

Crossrefs

Intersection of A005117 and A217400.

Cf. A077677, A077678, A077679, A077680, A077681, A077682, A077684, A077685.

Sequence in context: A302353 A059321 A217400 * A082797 A216994 A121027

Adjacent sequences: A077680 A077681 A077682 * A077684 A077685 A077686

Keyword

base,easy,nonn

Author

Amarnath Murthy, Nov 16 2002

Extensions

More terms from Sascha Kurz, Jan 28 2003

Status

approved