The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation. Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A290488 Lower ends of record gaps between numbers that are either prime or twice a prime. 5
 2, 7, 47, 181, 467, 526, 1069, 1262, 1327, 2477, 3274, 5119, 12854, 20809, 28229, 31397, 338038, 520462, 546391, 1050631, 1761206, 1964987, 3466943, 6084986, 27348829, 27915754, 111108769, 113652443, 230126378, 231902267, 327764081, 438981007, 581755318, 1837981547, 2489382697 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS The gap between 31397 and 31454 is due to the record prime gap between 31397 and 31469 being almost exactly twice the record prime gap between 15683 and 15727. LINKS Robert G. Wilson v, Table of n, a(n) for n = 1..37 FORMULA a(n) = A290489(n) - A290541(n). EXAMPLE a(3) = 47 because the next number that is a prime or twice a prime after 47 is 53, and that is a record gap of size 6. MATHEMATICA nxt[n_] := Block[{k = n +1}, While[ !PrimeQ[ k] && ! PrimeQ[ k/2], k++]; k]; p = 2; q = 3; mx = 0; lst = {}; While[p < 2500000000, If[q > mx + p, mx = q - p; AppendTo[ lst, p]]; p = q; q = nxt@ q]; lst (* Robert G. Wilson v, Aug 03 2017 *) CROSSREFS Cf. A001751, A290489, A290541. Sequence in context: A201481 A054555 A072287 * A276649 A091117 A056854 Adjacent sequences:  A290485 A290486 A290487 * A290489 A290490 A290491 KEYWORD nonn AUTHOR Bobby Jacobs, Aug 03 2017 EXTENSIONS a(11) onward from Robert G. Wilson v, Aug 03 2017 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 June 14 21:10 EDT 2021. Contains 345040 sequences. (Running on oeis4.)