This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A062926 a(1) = 1; a(n) is the smallest square of the form k*a(n-1) + 1, i.e., a(n) == 1 (mod a(n-1)), n > 2. 1
 1, 4, 9, 64, 961, 921600, 10070323201, 8364641212206750916, 1474140440485343846897708136232408225, 18289713383512490535096723656013877275576612770471865834506112296448576 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Robert Israel, Table of n, a(n) for n = 1..12 EXAMPLE a(5) = 961 = 15*64 + 1 where a(4) = 64. MATHEMATICA a[1] = 1; a[2] = 4; a[n_] := a[n] = (r = Reduce[k > Sqrt[a[n - 1]] && Mod[k^2, a[n - 1]] == 1, k, Integers] /. C[_] -> c; sel = Select[Table[r, {c, -1, 1}], #1 =!= False & ]; Min[k^2 /. ToRules /@ sel]); Table[a[n], {n, 1, 9}] (* Jean-François Alcover, Jan 12 2012 *) CROSSREFS Sequence in context: A184877 A055859 A162991 * A069020 A220189 A122956 Adjacent sequences:  A062923 A062924 A062925 * A062927 A062928 A062929 KEYWORD nonn,nice AUTHOR Amarnath Murthy, Jul 03 2001 EXTENSIONS More terms from Larry Reeves (larryr(AT)acm.org), Jul 10 2001 a(7) from Vladeta Jovovic, Jan 17 2004 a(9) by Jean-François Alcover, Jan 12 2012 a(10) from Robert Israel, Sep 18 2016 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 16 13:21 EDT 2019. Contains 324152 sequences. (Running on oeis4.)