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A077685 Squarefree numbers beginning with 9. 11
91, 93, 94, 95, 97, 901, 902, 903, 905, 906, 907, 910, 911, 913, 914, 915, 917, 919, 921, 922, 923, 926, 929, 930, 933, 934, 935, 937, 938, 939, 941, 942, 943, 946, 947, 949, 951, 953, 955, 957, 958, 959, 962, 965, 966, 967, 969, 970, 971, 973, 974, 977, 978 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Intersection of A005117 and A217402. - Michel Marcus, Sep 14 2013

Lower density is 1/(15*Pi^2), upper density is 2/(3*Pi^2). - Charles R Greathouse IV, Nov 05 2017

LINKS

Table of n, a(n) for n=1..53.

MATHEMATICA

Select[Range[1000], SquareFreeQ[#]&&First[IntegerDigits[#]]==9&] (* Harvey P. Dale, Dec 15 2013 *)

PROG

(PARI) isok(n) = issquarefree(n) && (digits(n)[1] == 9); \\ Michel Marcus, Sep 14 2013

CROSSREFS

Cf. A077677, A077678, A077679, A077680, A077681, A077682, A077683, A077684.

Sequence in context: A043803 A043811 A043820 * A129822 A321998 A020318

Adjacent sequences:  A077682 A077683 A077684 * A077686 A077687 A077688

KEYWORD

base,easy,nonn

AUTHOR

Amarnath Murthy, Nov 16 2002

EXTENSIONS

More terms from Sascha Kurz, Jan 28 2003

STATUS

approved

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Last modified November 19 08:44 EST 2019. Contains 329318 sequences. (Running on oeis4.)