The OEIS Foundation is supported by donations from users of the OEIS and by a grant from the Simons Foundation.

Thanks to everyone who made a donation during our annual appeal!
To see the list of donors, or make a donation, see the OEIS Foundation home page.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A321076 One of the two successive approximations up to 11^n for 11-adic integer sqrt(5). Here the 4 (mod 11) case (except for n = 0). 2
 0, 4, 48, 1258, 6582, 6582, 1456041, 10313846, 166211214, 1666723381, 18172357218, 95984631021, 2663789666520, 24632788303567, 162723636879291, 542473470462532, 33960458825787740, 493457757461509350, 3020692899957978205, 58619866034880293015, 547892589622196663343 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS For n > 0, a(n) is the unique solution to x^2 == 5 (mod 11^n) in the range [0, 11^n - 1] and congruent to 4 modulo 11. A321077 is the approximation (congruent to 7 mod 11) of another square root of 5 over the 11-adic field. LINKS Wikipedia, p-adic number FORMULA For n > 0, a(n) = 11^n - A321077(n). a(n) = Sum_{i=0..n-1} A321078(i)*11^i. EXAMPLE 4^2 = 16 = 5 + 1*11. 48^2 = 2304 = 5 + 19*11^2. 1258^2 = 1582564 = 5 + 1189*11^3. PROG (PARI) a(n) = truncate(sqrt(5+O(11^n))) CROSSREFS Cf. A321077, A321078. Sequence in context: A211045 A296838 A211049 * A166231 A191952 A013145 Adjacent sequences:  A321073 A321074 A321075 * A321077 A321078 A321079 KEYWORD nonn AUTHOR Jianing Song, Oct 27 2018 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 January 19 00:40 EST 2020. Contains 331030 sequences. (Running on oeis4.)