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A089244
Integer part of square root of the reciprocal of a prime number multiplied by 10 to the power of the integer part of the square root of the number.
0
7, 5, 44, 37, 301, 277, 2425, 2294, 2085, 18569, 17960, 164398, 156173, 152498, 145864, 1373605, 1301889, 1280368, 12216944, 11867816, 11704114, 11250879, 109764259, 105999788, 101534616, 995037190, 985329278, 966736489, 957826285, 940720868, 8873565094, 8737040566
OFFSET
2,1
COMMENTS
The sum of the reciprocals = 0.40100980056022072540219852776239... . Converges rapidly.
FORMULA
a(n) = floor( sqrt(1/x)*10^(floor(sqrt(x))) ), where x = prime(n).
MATHEMATICA
a[n_] := Module[{r = Sqrt[Prime[n]], ip, fp}, ip = Floor[r]; fp = r - ip; Floor[10^ip/r]]; Array[a, 40] (* Amiram Eldar, Jun 26 2024 *)
PROG
(PARI) rootrecipp(n) = { my(sr=0, r, ip, fp, y); forprime(x=2, n, r =sqrt(x); ip=floor(r); fp=r-ip; y=floor((1/r)*10^ip); print1(y", "); sr = sr + 1.0/y; ); print(); print(sr) }
CROSSREFS
Sequence in context: A376083 A163742 A202130 * A063003 A038271 A329008
KEYWORD
easy,nonn
AUTHOR
Cino Hilliard, Dec 11 2003
EXTENSIONS
More terms from Amiram Eldar, Jun 26 2024
STATUS
approved