[go: up one dir, main page]

login
A046036
Indices of the concatenation of the first n odd numbers (A019519) which are primes.
4
2, 10, 16, 34, 49, 2570
OFFSET
1,1
COMMENTS
No others with n <= 12000. - Eric W. Weisstein, Mar 01 2004
LINKS
H. Ibstedt, A Few Smarandache Integer Sequences, Smarandache Notions Journal, Vol. 8, No. 1-2-3, 1997, pp. 171-183.
Eric Weisstein's World of Mathematics, Consecutive Number Sequences
Eric Weisstein's World of Mathematics, Integer Sequence Primes
FORMULA
a(n) = (A066811(n)+1)/2. - Michel Marcus, Jan 31 2014
MATHEMATICA
Module[{nn=50, odds}, odds=Range[1, 2nn+1, 2]; Position[Table[ FromDigits[ Flatten[IntegerDigits/@Take[odds, n]]], {n, nn}], _?(PrimeQ[#]&)]]// Flatten (* The program generates the first 5 terms of the sequence. To generate the 6th, increase the value of nn to 2570 or more, but the program will take a long time to run. *) (* Harvey P. Dale, Jul 21 2021 *)
CROSSREFS
Sequence in context: A189329 A242089 A110761 * A131474 A249153 A276046
KEYWORD
nonn,base
STATUS
approved