This site is supported by donations to The OEIS Foundation.

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A002705 Sets with a congruence property. (Formerly M3673 N1497) 6
 0, 4, 40, 468, 5828, 76260, 1032444, 14316584, 202116108, 2893451652, 41886157564, 611902123284, 9007199254740, 133439988963012, 1987795697598012, 29752813022112180, 447193795726343004, 6746237832670921768, 102105221251235572188 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The values for k=1, Q(n,1) in table 1 on page 315 for n = 3,5,7,9,... are 0, 2, 6, 18, 62, 210, 728, 2570, 9198, 33288, 121574, 447394, 1657008, 6170930, 23091222, 86767016, 327235610, 1238188770, 4698767640 ... (see A262590), - R. J. Mathar, Oct 21 2015 REFERENCES N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS Rosa, Alexander; Znam, Stefan, A combinatorial problem in the theory of congruences (Russian with English summary), Mat.-Fys. Casopis Sloven. Akad. Vied 15 1965 49-59. [Annotated scanned copy.] Rosa, Alexander; Znam, Stefan, A remark on a combinatorial problem (Russian with English summary), Mat.-Fyz. Casopis Sloven. Akad. Vied 15 1965 313-316. [Annotated scanned copy] See Table 2. FORMULA See Maple code! MAPLE p := proc(r, s, k)     option remember;     if r = 0 then         1;     elif r < 0 then         0;     elif s < 0 then         0;     elif igcd(s, 2*k+1) > 1 then         procname(r, s-1, k) ;     else         procname(r, s-1, k)+procname(r-s, s-1, k) ;     end if; end proc: Q := proc(n, k)     local q, knrat, alpha, m ;     q := 0 ;     knrat := (2*k*n^2+n^2+k^2)/4/k ;     if type(knrat, 'integer') then         for alpha from 0 to knrat do             m := 2*n+n/k ;             if modp(2*alpha, m) = modp(knrat, m) then                 q := q+p(alpha, n+(n-k)/2/k, k) ;             end if;         end do:     end if;     q ; end proc: A002705 := proc(n)     nloc := 2+4*n ;     Q(nloc, 2) ; end proc: # R. J. Mathar, Oct 21 2015 CROSSREFS Cf. A002703, A002704, A262585, A262590. Sequence in context: A114468 A264112 A304447 * A235372 A034385 A249927 Adjacent sequences:  A002702 A002703 A002704 * A002706 A002707 A002708 KEYWORD nonn AUTHOR EXTENSIONS More terms from R. J. Mathar, Oct 21 2015 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 August 20 20:50 EDT 2019. Contains 326155 sequences. (Running on oeis4.)