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.

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

A062187 a(n+1) = a(n) - a(floor(n/2)), with a(0)=0, a(1)=1.

Original entry on oeis.org

0, 1, 1, 0, -1, -2, -3, -3, -3, -2, -1, 1, 3, 6, 9, 12, 15, 18, 21, 23, 25, 26, 27, 26, 25, 22, 19, 13, 7, -2, -11, -23, -35, -50, -65, -83, -101, -122, -143, -166, -189, -214, -239, -265, -291, -318, -345, -371, -397, -422, -447, -469, -491, -510, -529, -542, -555, -562, -569, -567, -565, -554, -543, -520, -497, -462
Offset: 0

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(6) = a(5) - a(2) = -2 - 1 = -3.
a(7) = a(6) - a(3) = -3 - 0 = -3.
		

Crossrefs

Programs

  • Python
    from itertools import islice
    from collections import deque
    def A062187_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
    A061287_list = list(islice(A062187_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

A179045 Triangle T(n,k), 1<=k<=n, read by rows, related to A033485.

Original entry on oeis.org

1, 2, 1, 3, 1, 1, 5, 2, 1, 1, 7, 3, 1, 1, 1, 10, 4, 2, 1, 1, 1, 13, 5, 3, 1, 1, 1, 1, 18, 7, 4, 2, 1, 1, 1, 1, 23, 9, 5, 3, 1, 1, 1, 1, 1, 30, 12, 6, 4, 2, 1, 1, 1, 1, 1, 37, 15, 7, 5, 3, 1, 1, 1, 1, 1, 1, 47, 19, 9, 6, 4, 2, 1, 1, 1, 1, 1, 1, 57, 23, 11, 7, 5, 3, 1, 1, 1, 1, 1, 1, 1, 70, 28, 14, 8, 6, 4
Offset: 1

Views

Author

Philippe Deléham, Jun 26 2010

Keywords

Comments

Column k=1 : A033485 ; column k=2 : A062188 ; row sums : A102378.

Examples

			Triangle begins : 1 ; 2,1 ; 3,1,1 ; 5,2,1,1 ; 7,3,1,1,1 ; ...
		

Crossrefs

Formula

T(n,k)=T(n-1,k)+T([n/2],k), T(n,n)=1, T(n,k)=0 if k>n.
Showing 1-3 of 3 results.