cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

A051853 Table of solutions to all possible Chinese Remainder Equations x = a1 mod p1, x = a2 mod p2, ..., x = an mod pn, where p1 - pn are the first n primes and each a1 - an varies between 1 and (its respective) p-1, with the leftmost a varying fastest.

Original entry on oeis.org

1, 1, 5, 1, 11, 7, 17, 13, 23, 19, 29, 1, 71, 127, 197, 43, 113, 169, 29, 121, 191, 37, 107, 163, 23, 79, 149, 31, 101, 157, 17, 73, 143, 199, 59, 151, 11, 67, 137, 193, 53, 109, 179, 61, 131, 187, 47, 103, 173, 19, 89, 181, 41, 97, 167, 13, 83, 139, 209, 1, 1541
Offset: 1

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Author

Antti Karttunen, Dec 13 1999

Keywords

Examples

			Rows have lengths 1,2,8,48,480,5760,92160,... (A005867(n)) and terms 1; 1,5; 1,11,7,17,13,23,19,29; 1,71,127,197,43,113,169,29,121,191,37,107,163,23,79,149,31,101,157,17,73,143,199,59,151,11,67,137,193,53,109,179,61,131,187,47,103,173,19,89,181,41,97,167,13,83,139,209;
		

Crossrefs

Cf. A051854.

Programs

  • Maple
    with(numtheory); incr_plist_from_left := proc(aa) local i,n,a; a := aa; n := nops(a); for i from 1 to n do if(a[i] < (ithprime(i)-1)) then a[i] := a[i]+1; RETURN(a); else a[i] := 1; fi; od; RETURN([op(a),1]); end;
    incr_plist_from_left_n_times := proc(aa,n) local a,i; a := aa; for i from 1 to n do a := incr_plist_from_left(a); od; RETURN(a); end; form_modlist := proc(a) local b,i; b := []; for i from 1 to nops(a) do b := [op(b),ithprime(i)]; od; RETURN(b); end;
    prim_chrem_left := proc(n) local r,m; r := incr_plist_from_left_n_times([],n); m := form_modlist(r); RETURN(chrem(r,m)); end;
  • Mathematica
    row[n_] := Module[{i}, pp = Prime[Range[n]]; iter = Sequence @@ Table[{i[k], 1, pp[[k]] - 1}, {k, n, 1, -1}]; Table[ChineseRemainder[Array[i, n], pp], iter // Evaluate] // Flatten]; Table[row[n], {n, 1, 5}] // Flatten (* Jean-François Alcover, Mar 06 2016 *)

Formula

a(n) = prim_chrem_left(n) (see Maple code)