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 1-2 of 2 results.

A062188 a(n+1) = a(n) + a(floor(n/2)), with a(0)=0, a(1)=1.

Original entry on oeis.org

0, 1, 1, 2, 3, 4, 5, 7, 9, 12, 15, 19, 23, 28, 33, 40, 47, 56, 65, 77, 89, 104, 119, 138, 157, 180, 203, 231, 259, 292, 325, 365, 405, 452, 499, 555, 611, 676, 741, 818, 895, 984, 1073, 1177, 1281, 1400, 1519, 1657, 1795, 1952, 2109, 2289, 2469, 2672, 2875, 3106
Offset: 0

Views

Author

Henry Bottomley, Jun 13 2001

Keywords

Examples

			a(6) = a(5)+a(2) = 4+1 = 5.
a(7) = a(6)+a(3) = 5+2 = 7.
		

Crossrefs

Programs

  • Magma
    [n le 2 select n-1 else  Self(n-1)+Self(Floor(n/2)): n in [1..60]]; // Vincenzo Librandi, Mar 03 2016
    
  • Mathematica
    Join[{0}, Nest[Append[#, #[[-1]] + #[[Quotient[Length@#, 2]]]] &, {1, 1}, 53]] (* Ivan Neretin, Mar 03 2016 *)
  • Python
    from itertools import islice
    from collections import deque
    def A062188_gen(): # generator of terms
        aqueue, f, b, a = deque([1]), True, 0, 1
        yield from (0,1)
        while True:
            a += b
            yield a
            aqueue.append(a)
            if f: b = aqueue.popleft()
            f = not f
    A062188_list = list(islice(A062188_gen(),40)) # Chai Wah Wu, Jun 08 2022

Formula

G.f. A(x) satisfies: A(x) = x * (1 + (1 + x)*A(x^2))/(1 - x). - Ilya Gutkovskiy, May 04 2019

A062186 a(n) = a(n-1) - a(floor(n/2)), with a(1)=1.

Original entry on oeis.org

1, 0, -1, -1, -1, 0, 1, 2, 3, 4, 5, 5, 5, 4, 3, 1, -1, -4, -7, -11, -15, -20, -25, -30, -35, -40, -45, -49, -53, -56, -59, -60, -61, -60, -59, -55, -51, -44, -37, -26, -15, 0, 15, 35, 55, 80, 105, 135, 165, 200, 235, 275, 315, 360, 405, 454, 503, 556, 609, 665, 721, 780, 839, 899, 959, 1020, 1081, 1141, 1201, 1260
Offset: 1

Views

Author

Henry Bottomley, Jun 13 2001

Keywords

Comments

Period of oscillations above and below the axis more than doubles at each cycle.

Examples

			a(14) = a(13) - a(7) = 5 - 1 = 4.
a(15) = a(14) - a(7) = 4 - 1 = 3.
		

Crossrefs

Programs

  • Python
    from itertools import islice
    from collections import deque
    def A062186_gen(): # generator of terms
        aqueue, f, b, a = deque([0]), True, 1, 0
        yield from (1,0)
        while True:
            a -= b
            yield a
            aqueue.append(a)
            if f: b = aqueue.popleft()
            f = not f
    A062186_list = list(islice(A062186_gen(),40)) # Chai Wah Wu, Jun 08 2022

Formula

G.f.: A(x) satisfies: A(x) = (x - (1 + x)*A(x^2))/(1 - x). - Ilya Gutkovskiy, May 04 2019
Showing 1-2 of 2 results.