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!)
 A202025 Position of second appearance of set of first n terms in the sequence of odd primes modulo 4. 0
 3, 4, 8, 16, 16, 19, 60, 221, 654, 654, 654, 654, 654, 30291, 30291, 30291, 30291, 250231, 342916, 342916, 472727, 1934365, 1934365, 11877702, 11877702, 11877702 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Next term, a(27) > 3*10^7. LINKS EXAMPLE Consider the sequence of odd primes modulo 4: S= 3, 1, 3, 3, 1, 1, 3, 3, 1, 3, 1, 1, 3, 3, 1, 3, 1,... . Then a(1)=3 because 2nd appearance of 3 is S(3), a(2)=4 because 2nd appearance of (3,1) begins at S(4), a(3)=8 because 2nd appearance of (3,1,3) begins at S(8), a(4)=16 because 2nd appearance of (3,1,3,3) begins at S(16). MATHEMATICA nn=3*10^7; s=Table[Mod[Prime[n], 4], {n, 2, nn}]; Reap[k1=2; Do[tn=Take[s, n]; Do[If[tn==Take[s, {k, k+n-1}], Sow[k]; k1=k; Break[]], {k, k1, nn-n-1}], {n, 26}]][[2, 1]] CROSSREFS Cf. A039702. Sequence in context: A027977 A165438 A293781 * A227615 A049894 A198633 Adjacent sequences:  A202022 A202023 A202024 * A202026 A202027 A202028 KEYWORD nonn AUTHOR Zak Seidov, Dec 09 2011 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 14 09:41 EST 2019. Contains 329979 sequences. (Running on oeis4.)