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.

Showing 1-3 of 3 results.

A298872 Solution (b(n)) of the system of 3 complementary equations in Comments.

Original entry on oeis.org

2, 6, 11, 18, 26, 35, 45, 57, 70, 84, 99, 116, 135, 155, 176, 198, 221, 245, 270, 298, 327, 357, 388, 420, 453, 487, 523, 560, 598, 637, 677, 718, 760, 804, 850, 897, 945, 994, 1044, 1095, 1147, 1200, 1254, 1309, 1365, 1423, 1482, 1543, 1605, 1668, 1732
Offset: 0

Views

Author

Clark Kimberling, Apr 18 2018

Keywords

Comments

Define sequences a(n), b(n), c(n) recursively, starting with a(0) = 1, b(0) = 2:
a(n) = least new;
b(n) = least new k >= a(n) + b(n-1);
c(n) = a(n) + 2 b(n);
where "least new k" means the least positive integer not yet placed. The sequences a,b,c partition the positive integers.

Examples

			n:   0    1    2    3    4    5    6    7    8   9
a:   1    4    5    7    8    9   10   12   13   14
b:   2    6   11   18   26   35   45   57   70   84
c:   3   16   27   43   60   30   79  100  126  153
		

Crossrefs

Programs

  • Mathematica
    z = 400;
    mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);
    a = {1}; b = {2}; c = {3};
    Do[{AppendTo[a, mex[Flatten[{a, b, c}], 1]],
       AppendTo[b, mex[Flatten[{a, b, c}], Last[a] + Last[b]]],
       AppendTo[c, Last[a] + 2 Last[b]]}, {z}];
    Take[a, 100]  (* A298871 *)
    Take[b, 100]  (* A298872 *)
    Take[c, 100]  (* A298873 *)

A298874 Solution (a(n)) of the system of 3 equations in Comments.

Original entry on oeis.org

1, 4, 5, 7, 8, 9, 10, 12, 13, 14, 15, 17, 19, 20, 21, 22, 23, 24, 25, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 44, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 58, 59, 61, 62, 63, 64, 65, 66, 67, 68, 69, 71, 72, 73, 74, 75, 76, 77, 78, 80, 81
Offset: 0

Views

Author

Clark Kimberling, Apr 19 2018

Keywords

Comments

Define sequences a(n), b(n), c(n) recursively, starting with a(0) = 1, b(0) = 2:
a(n) = least new;
b(n) = a(n) + b(n-1);
c(n) = a(n) + 2 b(n);
where "least new k" means the least positive integer not yet placed.
***
Do these sequences a,b,c partition the positive integers? They differ from the corresponding partitioning sequences A298871, A298872, and A298872. For example, A298872(56) = 2139, whereas A298875(56) = 2138.

Examples

			n:   0    1    2    3    4    5    6    7    8    9
a:   1    4    5    7    8    9   10   12   13   14
b:   2    6   11   18   26   35   45   57   70   84
c:   3   16   27   43   60   30   79  100  126  153
		

Crossrefs

Programs

  • Mathematica
    z = 200;
    mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);
    a = {1}; b = {2}; c = {3};
    Do[{AppendTo[a, mex[Flatten[{a, b, c}], 1]],
       AppendTo[b, Last[a] + Last[b]],
       AppendTo[c, Last[a] + 2 Last[b]]}, {z}];
    Take[a, 100]  (* A298874 *)
    Take[b, 100]  (* A298875 *)
    Take[c, 100]  (* A298876 *)

A298876 Solution (c(n)) of the system of 3 equations in Comments.

Original entry on oeis.org

3, 16, 27, 43, 60, 79, 100, 126, 153, 182, 213, 249, 289, 330, 373, 418, 465, 514, 565, 624, 683, 744, 807, 872, 939, 1008, 1082, 1157, 1234, 1313, 1394, 1477, 1562, 1652, 1746, 1841, 1938, 2037, 2138, 2241, 2346, 2453, 2562, 2673, 2786, 2904, 3023, 3147
Offset: 0

Views

Author

Clark Kimberling, Apr 19 2018

Keywords

Comments

Define sequences a(n), b(n), c(n) recursively, starting with a(0) = 1, b(0) = 2:
a(n) = least new;
b(n) = a(n) + b(n-1);
c(n) = a(n) + 2 b(n);
where "least new k" means the least positive integer not yet placed.
***
Do these sequences a,b,c partition the positive integers? They differ from the corresponding partitioning sequences A298871, A298872, and A298872. For example, A298872(56) = 2139, whereas A298875(56) = 2138.
Differs from A298873 first at n=56. - Georg Fischer, Oct 10 2018

Examples

			n:   0    1    2    3    4    5    6    7    8    9
a:   1    4    5    7    8    9   10   12   13   14
b:   2    6   11   18   26   35   45   57   70   84
c:   3   16   27   43   60   30   79  100  126  153
		

Crossrefs

Programs

  • Mathematica
    z = 200;
    mex[list_, start_] := (NestWhile[# + 1 &, start, MemberQ[list, #] &]);
    a = {1}; b = {2}; c = {3};
    Do[{AppendTo[a, mex[Flatten[{a, b, c}], 1]],
       AppendTo[b, Last[a] + Last[b]],
       AppendTo[c, Last[a] + 2 Last[b]]}, {z}];
    Take[a, 100]  (* A298874 *)
    Take[b, 100]  (* A298875 *)
    Take[c, 100]  (* A298876 *)
Showing 1-3 of 3 results.