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 1-10 of 42 results. Next

A363503 a(n+1) = 2*a(n) + A298338(n-1), with a(1) = 1.

Original entry on oeis.org

1, 3, 7, 15, 33, 71, 151, 319, 667, 1385, 2855, 5855, 11949, 24299, 49255, 99597, 200967, 404845, 814425, 1636581, 3285713, 6591853, 13216829, 26487447, 53062045, 106265431, 212759755, 425890401, 852381243, 1705734905, 3413043757, 6828635653, 13661395165
Offset: 1

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Author

Keywords

Comments

a(n) is an odd number that appears in m* = log(a(n)*phi^2) for the fermion condensate mass in odd dimensional and large N Gross-Neveu model at imaginary chemical potential and finite temperature.

Examples

			a(1) = 1;
a(2) = 2*a(1) + 1 = 2*1 + 1 = 3;
etc.
		

Crossrefs

Cf. A104457 (phi^2), A298338.

Programs

A298339 a(n) = a(n-1) + a(n-2) + a([n/2]), where a(0) = 1, a(1) = 2, a(2) = 3.

Original entry on oeis.org

1, 2, 3, 7, 13, 23, 43, 73, 129, 215, 367, 605, 1015, 1663, 2751, 4487, 7367, 11983, 19565, 31763, 51695, 83825, 136125, 220555, 357695, 579265, 938623, 1519551, 2460925, 3983227, 6448639, 10436353, 16892359, 27336079, 44240421, 71588483, 115848469
Offset: 0

Views

Author

Clark Kimberling, Feb 09 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 2; a[2] = 3;
    a[n_] := a[n] = a[n - 1] + a[n - 2] + a[Floor[n/2]];
    Table[a[n], {n, 0, 30}]  (* A298339 *)

A298400 a(n) = a(n-1) + a(n-2) - n*a(floor(n/2)), where a(0) = 1, a(1) = 1, a(2) = 1.

Original entry on oeis.org

1, 1, 1, -1, -4, -10, -8, -11, 13, 38, 151, 299, 546, 949, 1649, 2763, 4204, 6746, 10266, 16290, 23536, 36655, 53613, 83391, 123900, 193641, 292867, 460885, 707580, 1120644, 1745334, 2780325, 4391131, 7032724, 11194491, 17991105, 28816020, 46427283, 74624283
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 1; a[2] = 1; a[n_] := a[n] = a[n - 1] + a[n - 2] - n*a[Floor[n/2]];
    Table[a[n], {n, 0, 30}]  (* A298400 *)

A298401 a(n) = a(n-1) + a(n-2) - n*a(floor(n/2)), where a(0) = 1, a(1) = 2, a(2) = 3.

Original entry on oeis.org

1, 2, 3, -1, -10, -26, -30, -49, 1, 42, 303, 631, 1294, 2315, 4295, 7345, 11624, 18952, 29820, 47974, 71734, 113345, 171197, 270029, 410170, 647849, 997829, 1583173, 2460742, 3919360, 6159752, 9851417, 15639201, 25107026, 40101859, 64545565, 103573904
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 2; a[2] = 3;
    a[n_] := a[n] = a[n - 1] + a[n - 2] - n*a[Floor[n/2]];
    Table[a[n], {n, 0, 30}]  (* A298401 *)

A298402 a(n) = 2*a(n-1) - a(n-3) + a(floor(n/2)), where a(0) = 1, a(1) = 1, a(2) = 1.

Original entry on oeis.org

1, 1, 1, 2, 4, 8, 16, 30, 56, 100, 178, 308, 532, 902, 1526, 2550, 4254, 7038, 11626, 19098, 31336, 51224, 83658, 136288, 221884, 360642, 585898, 950814, 1542512, 2500652, 4053040, 6566118, 10635838, 17222890, 27886700, 45144600, 73077936, 118280798
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 1; a[2] = 1;
    a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + a[Floor[n/2]];
    Table[a[n], {n, 0, 90}]  (* A298402 *)

A298403 a(n) = 2*a(n-1) - a(n-3) + a(floor(n/2)), where a(0) = 1, a(1) = 2, a(2) = 3.

Original entry on oeis.org

1, 2, 3, 7, 15, 30, 60, 112, 209, 373, 664, 1149, 1985, 3366, 5695, 9517, 15877, 26268, 43392, 71280, 116956, 191184, 312237, 508667, 828135, 1346018, 2186735, 3548701, 5757079, 9333118, 15127052, 24506542, 39695843, 64280511, 104080748, 168491921, 272746723
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 2; a[2] = 3;
    a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + a[Floor[n/2]];
    Table[a[n], {n, 0, 90}]  (* A298403 *)

A298404 a(n) = 2*a(n-1) - a(n-3) + a(ceiling(n/2)), where a(0) = 1, a(1) = 1, a(2) = 1.

Original entry on oeis.org

1, 1, 1, 2, 4, 9, 18, 36, 67, 125, 223, 397, 687, 1187, 2013, 3406, 5692, 9496, 15711, 25953, 42633, 69952, 114348, 186750, 304235, 495309, 805055, 1307888, 2122480, 3443311, 5582140, 9047492, 14657365, 23742086, 38446176, 62250698, 100775021, 163129819
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 1; a[2] = 1;
    a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + a[Ceiling[n/2]];
    Table[a[n], {n, 0, 90}]  (* A298404  *)

A298405 a(n) = 2*a(n-1) - a(n-3) + a(ceiling(n/2)), where a(0) = 1, a(1) = 2, a(2) = 3.

Original entry on oeis.org

1, 2, 3, 8, 17, 39, 78, 156, 290, 541, 965, 1718, 2973, 5137, 8712, 14741, 24635, 41099, 67998, 112326, 184518, 302756, 494904, 808263, 1316743, 2143719, 3484312, 5660593, 9186179, 14902787, 24159722, 39157900, 63437648, 102756673, 166396545, 269423440
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 2; a[2] = 3;
    a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + a[Ceiling[n/2]];
    Table[a[n], {n, 0, 90}]  (* A298405  *)

A298406 a(n) = 2*a(n-1) - a(n-3) + a(floor(n/2)) + a(floor(n/3)) + ... + a(floor(n/n)), where a(0) = 1, a(1) = 1, a(2) = 1.

Original entry on oeis.org

1, 1, 1, 3, 8, 19, 42, 84, 163, 301, 547, 961, 1682, 2879, 4902, 8241, 13807, 22917, 37962, 62487, 102690, 168096, 274798, 448000, 729829, 1186797, 1928729, 3130905, 5080360, 8237339, 13352743, 21634097, 35045477, 56753250, 91896553, 148771833, 240830555
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 1; a[2] = 1;
    a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + Sum[a[Floor[n/k]], {k, 2, n}];
    Table[a[n], {n, 0, 90}]  (* A298406  *)
  • Python
    from functools import lru_cache
    @lru_cache(maxsize=None)
    def A298406(n):
        if n <= 2:
            return 1
        c, j = 2*A298406(n-1)-A298406(n-3), 2
        k1 = n//j
        while k1 > 1:
            j2 = n//k1 + 1
            c += (j2-j)*A298406(k1)
            j, k1 = j2, n//j2
        return c+n-j+1 # Chai Wah Wu, Mar 31 2021

A298407 a(n) = 2*a(n-1) - a(n-3) + a(floor(n/2)) + a(floor(n/3)) + ... + a(floor(n/n)), where a(0) = 1, a(1) = 2, a(2) = 3.

Original entry on oeis.org

1, 2, 3, 9, 23, 52, 113, 223, 431, 794, 1442, 2532, 4433, 7589, 12924, 21730, 36411, 60440, 100125, 164816, 270863, 443390, 724846, 1181713, 1925113, 3130488, 5087530, 8258585, 13400782, 21728136, 35221342, 57065559, 92441545, 149701409, 242400952, 392424193
Offset: 0

Views

Author

Clark Kimberling, Feb 10 2018

Keywords

Comments

a(n)/a(n-1) -> (1 + sqrt(5))/2, the golden ratio (A001622), so that (a(n)) has the growth rate of the Fibonacci numbers (A000045). See A298338 for a guide to related sequences.

Crossrefs

Programs

  • Mathematica
    a[0] = 1; a[1] = 2; a[2] = 3;
    a[n_] := a[n] = 2*a[n - 1] - a[n - 3] + Sum[a[Floor[n/k]], {k, 2, n}];
    Table[a[n], {n, 0, 90}]  (* A298407  *)
  • Python
    from functools import lru_cache
    @lru_cache(maxsize=None)
    def A298407(n):
        if n <= 2:
            return n+1
        c, j = 2*A298407(n-1)-A298407(n-3), 2
        k1 = n//j
        while k1 > 1:
            j2 = n//k1 + 1
            c += (j2-j)*A298407(k1)
            j, k1 = j2, n//j2
        return c+2*(n-j+1) # Chai Wah Wu, Mar 31 2021
Showing 1-10 of 42 results. Next