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.

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A191707 Dispersion of A016873, (numbers >1 and congruent to 1, 2, 3, or 4 mod 5), by antidiagonals.

Original entry on oeis.org

1, 2, 5, 3, 7, 10, 4, 9, 13, 15, 6, 12, 17, 19, 20, 8, 16, 22, 24, 26, 25, 11, 21, 28, 31, 33, 32, 30, 14, 27, 36, 39, 42, 41, 38, 35, 18, 34, 46, 49, 53, 52, 48, 44, 40, 23, 43, 58, 62, 67, 66, 61, 56, 51, 45, 29, 54, 73, 78, 84, 83, 77, 71, 64, 57, 50, 37
Offset: 1

Views

Author

Clark Kimberling, Jun 12 2011

Keywords

Comments

For a background discussion of dispersions and their fractal sequences, see A191426. For dispersions of congruence sequences mod 3 or mod 4, see A191655, A191663, A191667.
...
Each of the sequences (5n, n>1), (5n+1, n>1), (5n+2, n>=0), (5n+3, n>=0), (5n+4, n>=0), generates a dispersion. Each complement (beginning with its first term >1) also generates a dispersion. The ten sequences and dispersions are listed here:
...
A191702=dispersion of A008587 (5k, k>=1)
A191703=dispersion of A016861 (5k+1, k>=1)
A191704=dispersion of A016873 (5k+2, k>=0)
A191705=dispersion of A016885 (5k+3, k>=0)
A191706=dispersion of A016897 (5k+4, k>=0)
A191707=dispersion of A047201 (1, 2, 3, 4 mod 5 and >1)
A191708=dispersion of A047202 (0, 2, 3, 4 mod 5 and >1)
A191709=dispersion of A047207 (0, 1, 3, 4 mod 5 and >1)
A191710=dispersion of A032763 (0, 1, 2, 4 mod 5 and >1)
A191711=dispersion of A001068 (0, 1, 2, 3 mod 5 and >1)
...
EXCEPT for at most 2 initial terms (so that column 1 always starts with 1):
A191702 has 1st col A047201, all else A008587
A191703 has 1st col A047202, all else A016861
A191704 has 1st col A047207, all else A016873
A191705 has 1st col A032763, all else A016885
A191706 has 1st col A001068, all else A016897
A191707 has 1st col A008587, all else A047201
A191708 has 1st col A042968, all else A047203
A191709 has 1st col A042968, all else A047207
A191710 has 1st col A042968, all else A032763
A191711 has 1st col A042968, all else A001068
...
Regarding the dispersions A191670-A191673, there is a formula for sequences of the type "(a or b or c or d mod m)", (as in the relevant Mathematica programs):
...
If f(n)=(n mod 3), then (a,b,c,d,a,b,c,d,a,b,c,d,...) is given by a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n); so that for n>=1, "(a, b, c, d mod m)" is given by
a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n)+m*floor((n-1)/4)).

Examples

			Northwest corner:
1....2....3....4....6
5....7....9....12...16
10...13...17...22...28
15...19...24...31...39
20...26...33...42...53
25...32...41...52...66
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
    r = 40; r1 = 12;  c = 40; c1 = 12;
    a=2; b=3; c2=4; d=6; m[n_]:=If[Mod[n,4]==0,1,0];
    f[n_]:=a*m[n+3]+b*m[n+2]+c2*m[n+1]+d*m[n]+5*Floor[(n-1)/4]
    Table[f[n], {n, 1, 30}]  (* A047201 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]] (* A191707 *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191707  *)

A191708 Dispersion of A047202, (numbers >1 and congruent to 0, 2, 3, or 4 mod 5), by antidiagonals.

Original entry on oeis.org

1, 2, 6, 3, 8, 11, 4, 10, 14, 16, 5, 13, 18, 20, 21, 7, 17, 23, 25, 27, 26, 9, 22, 29, 32, 34, 33, 31, 12, 28, 37, 40, 43, 42, 39, 36, 15, 35, 47, 50, 54, 53, 49, 45, 41, 19, 44, 59, 63, 68, 67, 62, 57, 52, 46, 24, 55, 74, 79, 85, 84, 78, 72, 65, 58, 51, 30
Offset: 1

Views

Author

Clark Kimberling, Jun 12 2011

Keywords

Comments

For a background discussion of dispersions and their fractal sequences, see A191426. For dispersions of congruence sequences mod 3 or mod 4, see A191655, A191663, A191667.
...
Each of the sequences (5n, n>1), (5n+1, n>1), (5n+2, n>=0), (5n+3, n>=0), (5n+4, n>=0), generates a dispersion. Each complement (beginning with its first term >1) also generates a dispersion. The ten sequences and dispersions are listed here:
...
A191702=dispersion of A008587 (5k, k>=1)
A191703=dispersion of A016861 (5k+1, k>=1)
A191704=dispersion of A016873 (5k+2, k>=0)
A191705=dispersion of A016885 (5k+3, k>=0)
A191706=dispersion of A016897 (5k+4, k>=0)
A191707=dispersion of A047201 (1, 2, 3, 4 mod 5 and >1)
A191708=dispersion of A047202 (0, 2, 3, 4 mod 5 and >1)
A191709=dispersion of A047207 (0, 1, 3, 4 mod 5 and >1)
A191710=dispersion of A032763 (0, 1, 2, 4 mod 5 and >1)
A191711=dispersion of A001068 (0, 1, 2, 3 mod 5 and >1)
...
EXCEPT for at most 2 initial terms (so that column 1 always starts with 1):
A191702 has 1st col A047201, all else A008587
A191703 has 1st col A047202, all else A016861
A191704 has 1st col A047207, all else A016873
A191705 has 1st col A032763, all else A016885
A191706 has 1st col A001068, all else A016897
A191707 has 1st col A008587, all else A047201
A191708 has 1st col A042968, all else A047203
A191709 has 1st col A042968, all else A047207
A191710 has 1st col A042968, all else A032763
A191711 has 1st col A042968, all else A001068
...
Regarding the dispersions A191670-A191673, there is a formula for sequences of the type "(a or b or c or d mod m)", (as in the relevant Mathematica programs):
...
If f(n)=(n mod 3), then (a,b,c,d,a,b,c,d,a,b,c,d,...) is given by a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n); so that for n>=1, "(a, b, c, d mod m)" is given by
a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n)+m*floor((n-1)/4)).

Examples

			Northwest corner:
1....2....3....4....5
6....8....10...13...17
11...14...18...23...29
16...20...25...32...40
21...27...34...43...54
26...33...42...53...67
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
    r = 40; r1 = 12;  c = 40; c1 = 12;
    a=2; b=3; c2=4; d=5; m[n_]:=If[Mod[n,4]==0,1,0];
    f[n_]:=a*m[n+3]+b*m[n+2]+c2*m[n+1]+d*m[n]+5*Floor[(n-1)/4]
    Table[f[n], {n, 1, 30}]  (* A047202 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]] (* A191708 *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191708  *)

A191709 Dispersion of A047202, (numbers >1 and congruent to 0, 1, 3, or 4 mod 5), by antidiagonals.

Original entry on oeis.org

1, 3, 2, 5, 4, 7, 8, 6, 10, 12, 11, 9, 14, 16, 17, 15, 13, 19, 21, 23, 22, 20, 18, 25, 28, 30, 29, 27, 26, 24, 33, 36, 39, 38, 35, 32, 34, 31, 43, 46, 50, 49, 45, 41, 37, 44, 40, 55, 59, 64, 63, 58, 53, 48, 42, 56, 51, 70, 75, 81, 80, 74, 68, 61, 54, 47, 71
Offset: 1

Views

Author

Clark Kimberling, Jun 12 2011

Keywords

Comments

For a background discussion of dispersions and their fractal sequences, see A191426. For dispersions of congruence sequences mod 3 or mod 4, see A191655, A191663, A191667.
...
Each of the sequences (5n, n>1), (5n+1, n>1), (5n+2, n>=0), (5n+3, n>=0), (5n+4, n>=0), generates a dispersion. Each complement (beginning with its first term >1) also generates a dispersion. The ten sequences and dispersions are listed here:
...
A191702=dispersion of A008587 (5k, k>=1)
A191703=dispersion of A016861 (5k+1, k>=1)
A191704=dispersion of A016873 (5k+2, k>=0)
A191705=dispersion of A016885 (5k+3, k>=0)
A191706=dispersion of A016897 (5k+4, k>=0)
A191707=dispersion of A047201 (1, 2, 3, 4 mod 5 and >1)
A191708=dispersion of A047202 (0, 2, 3, 4 mod 5 and >1)
A191709=dispersion of A047207 (0, 1, 3, 4 mod 5 and >1)
A191710=dispersion of A032763 (0, 1, 2, 4 mod 5 and >1)
A191711=dispersion of A001068 (0, 1, 2, 3 mod 5 and >1)
...
EXCEPT for at most 2 initial terms (so that column 1 always starts with 1):
A191702 has 1st col A047201, all else A008587
A191703 has 1st col A047202, all else A016861
A191704 has 1st col A047207, all else A016873
A191705 has 1st col A032763, all else A016885
A191706 has 1st col A001068, all else A016897
A191707 has 1st col A008587, all else A047201
A191708 has 1st col A042968, all else A047203
A191709 has 1st col A042968, all else A047207
A191710 has 1st col A042968, all else A032763
A191711 has 1st col A042968, all else A001068
...
Regarding the dispersions A191670-A191673, there is a formula for sequences of the type "(a or b or c or d mod m)", (as in the relevant Mathematica programs):
...
If f(n)=(n mod 3), then (a,b,c,d,a,b,c,d,a,b,c,d,...) is given by a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n); so that for n>=1, "(a, b, c, d mod m)" is given by
a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n)+m*floor((n-1)/4)).

Examples

			Northwest corner:
1....3....5....8....11
2....4....6....9....13
7....10...14...19...25
12...16...21...28...36
17...23...30...39...50
22...29...38...49...63
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
    r = 40; r1 = 12;  c = 40; c1 = 12;
    a=3; b=4; c2=5; d=6; m[n_]:=If[Mod[n,4]==0,1,0];
    f[n_]:=a*m[n+3]+b*m[n+2]+c2*m[n+1]+d*m[n]+5*Floor[(n-1)/4]
    Table[f[n], {n, 1, 30}]  (* A047207 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]] (* A191709 *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191709  *)

A191710 Dispersion of A032763, (numbers >1 and congruent to 0, 1, 2, or 4 mod 5), by antidiagonals.

Original entry on oeis.org

1, 2, 3, 4, 5, 8, 6, 7, 11, 13, 9, 10, 15, 17, 18, 12, 14, 20, 22, 24, 23, 16, 19, 26, 29, 31, 30, 28, 21, 25, 34, 37, 40, 39, 36, 33, 27, 32, 44, 47, 51, 50, 46, 42, 38, 35, 41, 56, 60, 65, 64, 59, 54, 49, 43, 45, 52, 71, 76, 82, 81, 75, 69, 62, 55, 48, 57
Offset: 1

Views

Author

Clark Kimberling, Jun 12 2011

Keywords

Comments

For a background discussion of dispersions and their fractal sequences, see A191426. For dispersions of congruence sequences mod 3 or mod 4, see A191655, A191663, A191667.
...
Each of the sequences (5n, n>1), (5n+1, n>1), (5n+2, n>=0), (5n+3, n>=0), (5n+4, n>=0), generates a dispersion. Each complement (beginning with its first term >1) also generates a dispersion. The ten sequences and dispersions are listed here:
...
A191702=dispersion of A008587 (5k, k>=1)
A191703=dispersion of A016861 (5k+1, k>=1)
A191704=dispersion of A016873 (5k+2, k>=0)
A191705=dispersion of A016885 (5k+3, k>=0)
A191706=dispersion of A016897 (5k+4, k>=0)
A191707=dispersion of A047201 (1, 2, 3, 4 mod 5 and >1)
A191708=dispersion of A047202 (0, 2, 3, 4 mod 5 and >1)
A191709=dispersion of A047207 (0, 1, 3, 4 mod 5 and >1)
A191710=dispersion of A032763 (0, 1, 2, 4 mod 5 and >1)
A191711=dispersion of A001068 (0, 1, 2, 3 mod 5 and >1)
...
EXCEPT for at most 2 initial terms (so that column 1 always starts with 1):
A191702 has 1st col A047201, all else A008587
A191703 has 1st col A047202, all else A016861
A191704 has 1st col A047207, all else A016873
A191705 has 1st col A032763, all else A016885
A191706 has 1st col A001068, all else A016897
A191707 has 1st col A008587, all else A047201
A191708 has 1st col A042968, all else A047203
A191709 has 1st col A042968, all else A047207
A191710 has 1st col A042968, all else A032763
A191711 has 1st col A042968, all else A001068
...
Regarding the dispersions A191670-A191673, there is a formula for sequences of the type "(a or b or c or d mod m)", (as in the relevant Mathematica programs):
...
If f(n)=(n mod 3), then (a,b,c,d,a,b,c,d,a,b,c,d,...) is given by a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n); so that for n>=1, "(a, b, c, d mod m)" is given by
a*f(n+3)+b*f(n+2)+c*f(n+1)+d*f(n)+m*floor((n-1)/4)).

Examples

			Northwest corner:
1....2....4....6....9
3....5....7....10...14
8....11...15...20...26
13...17...22...29...37
18...24...31...40...51
23...30...39...50...64
		

Crossrefs

Programs

  • Mathematica
    (* Program generates the dispersion array T of the increasing sequence f[n] *)
    r = 40; r1 = 12;  c = 40; c1 = 12;
    a=2; b=4; c2=5; d=6; m[n_]:=If[Mod[n,4]==0,1,0];
    f[n_]:=a*m[n+3]+b*m[n+2]+c2*m[n+1]+d*m[n]+5*Floor[(n-1)/4]
    Table[f[n], {n, 1, 30}]  (* A032763 *)
    mex[list_] := NestWhile[#1 + 1 &, 1, Union[list][[#1]] <= #1 &, 1, Length[Union[list]]]
    rows = {NestList[f, 1, c]};
    Do[rows = Append[rows, NestList[f, mex[Flatten[rows]], r]], {r}];
    t[i_, j_] := rows[[i, j]];
    TableForm[Table[t[i, j], {i, 1, 10}, {j, 1, 10}]] (* A191710 *)
    Flatten[Table[t[k, n - k + 1], {n, 1, c1}, {k, 1, n}]] (* A191710  *)

A047226 Numbers that are congruent to {0, 1, 2, 3, 4} mod 6; a(n)=floor(6(n-1)/5).

Original entry on oeis.org

0, 1, 2, 3, 4, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 42, 43, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 78, 79
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    [n: n in [0..100] | n mod 6 in [0..4]]; // Vincenzo Librandi, Jan 06 2013
  • Maple
    A047226 := proc(n)
        option remember;
        if n <= 6 then
            op(n,[0,1,2,3,4,6]) ;
        else
            procname(n-1)+procname(n-5)-procname(n-6) ;
        end if;
    end proc: # R. J. Mathar, Jul 25 2013
  • Mathematica
    Select[Range[0, 100], MemberQ[{0, 1, 2, 3, 4}, Mod[#, 6]]&] (* Vincenzo Librandi, Jan 06 2013 *)

Formula

G.f.: x^2*(1+x+x^2+x^3+2*x^4) / ( (x^4+x^3+x^2+x+1)*(x-1)^2 ). - R. J. Mathar, Oct 08 2011
From Wesley Ivan Hurt, Sep 17 2015, Jul 16 2013: (Start)
a(n) = floor( 6*(n-1)/5 ).
a(n) = a(n-1) + a(n-5) - a(n-6) for n>6.
a(n) = n - 1 + floor((n-1)/5). (End)
Sum_{n>=2} (-1)^n/a(n) = (9-4*sqrt(3))*Pi/36 + log(2+sqrt(3))/(2*sqrt(3)) + log(2)/6. - Amiram Eldar, Dec 17 2021

Extensions

Explicit formula added to definition by M. F. Hasler, Oct 05 2014

A047368 Numbers that are congruent to {0, 1, 2, 3, 4, 5} mod 7; a(n)=floor(7(n-1)/6).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 14, 15, 16, 17, 18, 19, 21, 22, 23, 24, 25, 26, 28, 29, 30, 31, 32, 33, 35, 36, 37, 38, 39, 40, 42, 43, 44, 45, 46, 47, 49, 50, 51, 52, 53, 54, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 67, 68, 70, 71, 72, 73, 74, 75, 77
Offset: 1

Views

Author

Keywords

Crossrefs

Programs

  • Magma
    [n : n in [0..100] | n mod 7 in [0..5]]; // Wesley Ivan Hurt, Jun 15 2016
  • Maple
    A047368:=n->(42*n-57-3*cos(Pi*n)-4*sqrt(3)*cos((4*n+1)*Pi/6)-12*sin((1-2*n)*Pi/6))/36: seq(A047368(n), n=1..100); # Wesley Ivan Hurt, Jun 15 2016
  • Mathematica
    Select[Range[0, 100], MemberQ[{0, 1, 2, 3, 4, 5}, Mod[#, 7]] &] (* Wesley Ivan Hurt, Jun 15 2016 *)
    LinearRecurrence[{1, 0, 0, 0, 0, 1, -1}, {0, 1, 2, 3, 4, 5, 7}, 100] (* Vincenzo Librandi, Jun 16 2016 *)
  • PARI
    a(n)=(n-1)*7\6 \\ M. F. Hasler, Oct 05 2014
    

Formula

G.f.: x^2*(1+x+x^2+x^3+x^4+2*x^5) / ( (1+x)*(1+x+x^2)*(x^2-x+1)*(x-1)^2 ). - R. J. Mathar, Dec 04 2011
From Wesley Ivan Hurt, Jun 15 2016: (Start)
a(n) = a(n-1) + a(n-6) - a(n-7) for n>7.
a(n) = (42*n-57-3*cos(Pi*n)-4*sqrt(3)*cos((4*n+1)*Pi/6)-12*sin((1-2*n)*Pi/6))/36.
a(6k) = 7k-2, a(6k-1) = 7k-3, a(6k-2) = 7k-4, a(6k-3) = 7k-5, a(6k-4) = 7k-6, a(6k-5) = 7k-7. (End)

Extensions

Crossrefs and explicit formula in name added by M. F. Hasler, Oct 05 2014

A248375 a(n) = floor(9*n/8).

Original entry on oeis.org

0, 1, 2, 3, 4, 5, 6, 7, 9, 10, 11, 12, 13, 14, 15, 16, 18, 19, 20, 21, 22, 23, 24, 25, 27, 28, 29, 30, 31, 32, 33, 34, 36, 37, 38, 39, 40, 41, 42, 43, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 63, 64, 65, 66, 67, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 79, 81, 82, 83, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95
Offset: 0

Views

Author

M. F. Hasler, Oct 05 2014

Keywords

Comments

Also: numbers not congruent to 8 (mod 9), or numbers whose base-9 expansion does not end in the digit "8".
Paz proves that for all n>0 there is a prime in Breusch's interval [n; a(n+3)], cf A248371.

Crossrefs

Programs

  • Magma
    [Floor(9*n/8): n in [0..90]]; // Bruno Berselli, Oct 06 2014
  • Mathematica
    Table[Floor[9 n/8], {n, 0, 90}] (* Bruno Berselli, Oct 06 2014 *)
  • PARI
    a(n)=9*n\8
    

Formula

G.f.: x*(1 + x + x^2 + x^3 + x^4 + x^5 + x^6 + 2*x^7) / ((1 + x)*(1 - x)^2*(1 + x^2)*(1 + x^4)). [Bruno Berselli, Oct 06 2014]
a(n) = n + floor(n/8) = a(n-1) + a(n-8) - a(n-9). [Bruno Berselli, Oct 06 2014]
a(n) = A168183(n+1) - 1. - Philippe Deléham, Dec 05 2013

A249547 a(n) = (10*n^2+8*n-1+(-1)^n)/8.

Original entry on oeis.org

0, 2, 7, 14, 24, 36, 51, 68, 88, 110, 135, 162, 192, 224, 259, 296, 336, 378, 423, 470, 520, 572, 627, 684, 744, 806, 871, 938, 1008, 1080, 1155, 1232, 1312, 1394, 1479, 1566, 1656, 1748, 1843, 1940, 2040, 2142, 2247, 2354, 2464, 2576, 2691, 2808, 2928, 3050
Offset: 0

Views

Author

Wesley Ivan Hurt, Oct 31 2014

Keywords

Comments

a(n) is the number of lattice points (x,y) in the coordinate plane bounded by y < 3x, y >= x/2 and x <= n.
a(n)+1 is the number of lattice points bounded by y <= 3x, y >= x/2 and x <= n.

Crossrefs

Programs

  • Magma
    [(10*n^2+8*n-1+(-1)^n)/8 : n in [0..50]];
    
  • Maple
    A249547:=n->(10*n^2+8*n-1+(-1)^n)/8: seq(A249547(n), n=0..100);
  • Mathematica
    Table[(10*n^2 + 8 n - 1 + (-1)^n)/8 , {n, 0, 50}]
  • PARI
    a(n) = (10*n^2+8*n-1+(-1)^n)/8; \\ Michel Marcus, Nov 04 2014
    
  • PARI
    concat(0, Vec(x*(2+3*x)/((1-x)^3*(1+x)) + O(x^100))) \\ Altug Alkan, Oct 28 2015

Formula

G.f.: x*(2+3*x)/((1-x)^3*(1+x)).
a(n) = 2*a(n-1)-2*a(n-3)+a(n-4) for n>3.
a(n) = A004526(n) + A226292(n), for n>0.
a(n) = Sum_{i=0..n} A001068(2*i). - Wesley Ivan Hurt, May 06 2016
E.g.f.: (x*(9 + 5*x)*exp(x) - sinh(x))/4. - Ilya Gutkovskiy, May 06 2016
a(2n) = A168668(n). a(2n-1) = A135706(n). - Wesley Ivan Hurt, May 09 2016

A086848 First differences are formed by interleaving {2^k - 1, k = 1, 2, 3, ...} and {11*k, k = 5, 4, 3, ...}.

Original entry on oeis.org

42, 43, 98, 101, 145, 152, 185, 200, 222, 253, 264, 327, 327, 454, 443, 698, 676, 1187, 1154, 2177, 2133, 4180, 4125, 8220, 8154, 16345, 16268, 32651, 32563, 65330, 65231, 130766, 130656, 261727, 261606, 523749, 523617, 1047904
Offset: 1

Views

Author

Michael M. Taylor, Aug 09 2003

Keywords

Comments

A version of this was given as a puzzle somewhere.
There are infinitely many solutions to the stated sequence name producing the specified interleaving as a first difference. I assume there was some other condition given in the puzzle that arrived at this particular solution. - Ray Chandler, May 07 2025

Crossrefs

Formula

Empirical g.f.: x*(48*x^6+34*x^4-x^3-113*x^2+x+42) / ((x-1)^3*(x+1)^2*(2*x^2-1)). - Colin Barker, Mar 05 2013
Conjectured g.f. above confirmed. Interleaving of two linear recurrences is another linear recurrence, as is the first difference. - Ray Chandler, May 07 2025

A087098 Partial sums of A087100.

Original entry on oeis.org

0, 1, 12, 15, 37, 44, 77, 92, 136, 167, 222, 285, 351, 478, 555, 810, 898, 1409, 1508, 2531, 2641, 4688, 4809, 8904, 9036, 17227, 17370, 33753, 33907, 66674, 66839, 132374, 132550, 263621, 263808, 525951, 526149, 1050436, 1050645, 2099220
Offset: 0

Views

Author

Jeremy Gardiner, Aug 10 2003

Keywords

Crossrefs

Programs

  • Mathematica
    Accumulate[Rest[With[{nn=30},Riffle[2^Range[0,nn]-1,11Range[0,nn]]]]] (* Harvey P. Dale, Feb 13 2017 *)

Formula

From Chai Wah Wu, Feb 02 2021: (Start)
a(n) = a(n-1) + 4*a(n-2) - 4*a(n-3) - 5*a(n-4) + 5*a(n-5) + 2*a(n-6) - 2*a(n-7) for n > 6.
G.f.: x*(-22*x^3 - x^2 + 11*x + 1)/((x - 1)^3*(x + 1)^2*(2*x^2 - 1)). (End)
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