This site is supported by donations to The OEIS Foundation.

 Please make a donation to keep the OEIS running. We are now in our 55th year. In the past year we added 12000 new sequences and reached 8000 citations (which often say "discovered thanks to the OEIS"). We need to raise money to hire someone to manage submissions, which would reduce the load on our editors and speed up editing. Other ways to donate

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A227509 a(n) = difference between the 2 smallest prime numbers > 10^n. 1
 2, 2, 4, 2, 16, 30, 60, 30, 2, 14, 16, 22, 14, 36, 54, 8, 10, 6, 36, 90, 76, 48, 40, 42, 210, 56, 176, 126, 60, 42, 24, 204, 188, 36, 34, 56, 20, 38, 34, 18, 170, 106, 22, 26, 112, 416, 160, 24, 60, 296, 126, 64, 30, 126, 136, 6, 84, 10, 174, 60, 286, 126, 186, 6 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS (Sum_{n=1..N} a(n)/n)/N appears to tend to log(10) as N increases. LINKS Pierre CAMI, Table of n, a(n) for n = 1..1825 EXAMPLE 10^1+1=11 is prime as is 13 so a(1)=2. 10^2+1=101 is prime as is 103 so a(2)=2. MATHEMATICA spn[n_]:=Module[{a=NextPrime[10^n]}, NextPrime[a]-a]; Array[spn, 70] (* Harvey P. Dale, Sep 01 2017 *) PROG PFGW & SCRIPT SCRIPT DIM n, 0 DIM k DIM g DIMS t OPENFILEOUT myfile, a(n).txt LABEL a SET n, n+1 SET k, -1 LABEL b SET k, k+2 SETS t, %d, %d\,; n; k PRP 10^n+k, t IF ISPRP THEN GOTO c GOTO b LABEL c SET g, k LABEL d SET k, k+2 SETS t, %d, %d\,; n; k PRP 10^n+k, t IF ISPRP THEN GOTO e GOTO d LABEL e SET g, k-g SETS t, %d, %d, %d\,; n; g; k WRITE myfile, t GOTO a CROSSREFS Sequence in context: A159749 A227293 A102416 * A279094 A299148 A129243 Adjacent sequences:  A227506 A227507 A227508 * A227510 A227511 A227512 KEYWORD nonn AUTHOR Pierre CAMI, Jul 14 2013 STATUS approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recent
The OEIS Community | Maintained by The OEIS Foundation Inc.

Last modified December 10 14:27 EST 2019. Contains 329896 sequences. (Running on oeis4.)