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A077684
Squarefree numbers with 8 as their initial (leftmost) digit.
11
82, 83, 85, 86, 87, 89, 802, 803, 805, 806, 807, 809, 811, 813, 814, 815, 817, 818, 821, 822, 823, 826, 827, 829, 830, 831, 834, 835, 838, 839, 842, 843, 849, 851, 853, 854, 857, 858, 859, 861, 862, 863, 865, 866, 869, 870, 871, 874, 877, 878, 879, 881, 883
OFFSET
1,1
COMMENTS
Intersection of A005117 and A217401. - Michel Marcus, Sep 14 2013
Lower density is 3/(40*Pi^2), upper density is 20/(27*Pi^2). - Charles R Greathouse IV, Nov 05 2017
LINKS
MATHEMATICA
Select[Range[900], SquareFreeQ[#]&&First[IntegerDigits[#]]==8&] (* Harvey P. Dale, Feb 22 2011 *)
PROG
(PARI) is(n)=n>81 && digits(n)[1]==8 && issquarefree(n) \\ Charles R Greathouse IV, Nov 05 2017
KEYWORD
base,easy,nonn
AUTHOR
Amarnath Murthy, Nov 16 2002
EXTENSIONS
More terms from Sascha Kurz, Jan 28 2003
Definition clarified by Harvey P. Dale, Feb 22 2011
STATUS
approved