A132174 Index of starting position of n-th generation of terms in A063882.

1, 5, 10, 21, 44, 92, 189, 385, 778, 1565, 3141, 6294, 12602, 25219, 50454, 100926, 201871, 403763, 807548, 1615119, 3230263, 6460552, 12921132, 25842293, 51684616, 103369264, 206738561, 413477157, 826954350, 1653908737, 3307817513, 6615635066, 13231270174

Offset

1,2

Links

Chai Wah Wu, Table of n, a(n) for n = 1..1002

B. Balamohan, A. Kuznetsov and S. Tanny, On the behavior of a variant of Hofstadter's Q-sequence, J. Integer Sequences, Vol. 10 (2007), #07.7.1.

Index entries for Hofstadter-type sequences

Index entries for linear recurrences with constant coefficients, signature (3, -2, 0, 0, 1, -3, 2).

Formula

From Chai Wah Wu, May 17 2017: (Start)

a(n) = 3*a(n-1) - 2*a(n-2) + a(n-5) - 3*a(n-6) + 2*a(n-7) for n > 8.

G.f.: x*(-5*x^7 + x^6 - x^5 - x^4 - x^3 + 3*x^2 - 2*x - 1)/((x - 1)^2*(2*x - 1)*(x^4 + x^3 + x^2 + x + 1)). (End)

Prog

(Python)
from __future__ import division
def A132174(n):
    if n == 1:
        return 1
    if n == 2:
        return 5
    h, m = divmod(n - 3, 5)
    return (382*2**(5*h + m)-10*2**m)//31- 7*h - m -(1 if m==3 else (-1 if m==4 else 2)) # Chai Wah Wu, May 17 2017

Crossrefs

Sequence in context: A280077 A372054 A295952 * A297301 A132461 A255150

Adjacent sequences: A132171 A132172 A132173 * A132175 A132176 A132177

Keyword

nonn

Author

N. J. A. Sloane, Nov 07 2007

Extensions

More terms from Chai Wah Wu, May 17 2017

Status

approved