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

Author

Amarnath Murthy, Nov 16 2002

Keywords

• base
• easy
• nonn

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

Crossrefs

Intersection of A005117 and A217400.

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

Programs

PARI

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

Extensions

More terms from Sascha Kurz, Jan 28 2003