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A098147 Difference between first odd semiprime > 10^n and 10^n. 7
5, 11, 3, 1, 1, 1, 1, 1, 13, 3, 7, 7, 15, 13, 3, 3, 15, 7, 1, 19, 3, 19, 13, 29, 7, 7, 3, 27, 13, 3, 1, 9, 9, 9, 27, 7, 3, 7, 49, 55, 81, 3, 3, 9, 7, 11, 69, 7, 19, 13, 39, 7, 1, 3, 13, 13, 39, 77, 27, 63, 31, 51, 19, 9, 27, 3, 1, 39, 19, 41, 21, 67, 37, 63, 69, 33, 3, 9, 37, 67, 121, 9, 21 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..83.

Dario Alpern, Factorization using the Elliptic Curve Method.

FORMULA

a(n)=A098146(n)-10^n.

EXAMPLE

a(2)=11: The first odd semiprime following 10^2 is 111=3*37; 111-100=11.

CROSSREFS

Cf. A098146, A033873 difference between first prime > 10^n and 10^n.

Sequence in context: A159199 A125683 A125685 * A100298 A066461 A117069

Adjacent sequences:  A098144 A098145 A098146 * A098148 A098149 A098150

KEYWORD

nonn

AUTHOR

Hugo Pfoertner, Aug 28 2004

STATUS

approved

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Last modified August 5 01:51 EDT 2021. Contains 346456 sequences. (Running on oeis4.)