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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A176415 Periodic sequence: repeat 7,1.

Original entry on oeis.org

7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7, 1, 7
Offset: 0

Views

Author

Klaus Brockhaus, Apr 17 2010

Keywords

Comments

Interleaving of A010727 and A000012.
Also continued fraction expansion of (7+sqrt(77))/2.
Also decimal expansion of 71/99.
Essentially first differences of A047521.
Binomial transform of A176414.
Inverse binomial transform of 2*A020707 preceded by 7.
Exp( Sum_{n >= 1} a(n)*x^n/n ) = 1 + x + 4*x^2 + 4*x^3 + 10*x^4 + 10*x^5 + ... is the o.g.f. for A058187. - Peter Bala, Mar 13 2015

Crossrefs

Cf. A010727 (all 7's sequence), A000012 (all 1's sequence), A092290 (decimal expansion of (7+sqrt(77))/2), A010688 (repeat 1, 7), A047521 (congruent to 0 or 7 mod 8), A176414 (expansion of (7+8*x)/(1+2*x)), A020707 (2^(n+2)), A058187.

Programs

  • Magma
    &cat[ [7, 1]: n in [0..52] ];
    [ 4+3*(-1)^n: n in [0..104] ];
    
  • Mathematica
    PadRight[{},120,{7,1}] (* Harvey P. Dale, Dec 30 2018 *)
  • PARI
    a(n)=7-n%2*6 \\ Charles R Greathouse IV, Oct 28 2011

Formula

a(n) = 4+3*(-1)^n.
a(n) = a(n-2) for n > 1; a(0) = 7, a(1) = 1.
a(n) = -a(n-1)+8 for n > 0; a(0) = 7.
a(n) = 7*((n+1) mod 2)+(n mod 2).
a(n) = A010688(n+1).
G.f.: (7+x)/(1-x^2).
Dirichglet g.f.: (1+6*2^(-s))*zeta(s). - R. J. Mathar, Apr 06 2011
Multiplicative with a(2^e) = 7, and a(p^e) = 1 for p >= 3. - Amiram Eldar, Jan 01 2023

A277084 Pisot sequence L(4,14).

Original entry on oeis.org

4, 14, 49, 172, 604, 2122, 7456, 26198, 92052, 323444, 1136489, 3993295, 14031289, 49301911, 173232725, 608689936, 2138761243, 7514991434, 26405516950, 92781386582, 326007088306, 1145495077635, 4024940008834, 14142480741305, 49692606865991, 174605518105877
Offset: 0

Views

Author

Ilya Gutkovskiy, Sep 29 2016

Keywords

Comments

There is no simple g.f. - Ilya Gutkovskiy, May 23 2019

Crossrefs

Cf. A008776 for definitions of Pisot sequences.
Cf. A010904 (Pisot sequence E(4,14)), A251221 (seems to be Pisot sequence P(4,14)).

Programs

  • Mathematica
    RecurrenceTable[{a[0] == 4, a[1] == 14, a[n] == Ceiling[a[n - 1]^2/a[n - 2]]}, a, {n, 25}]

Formula

a(n) = ceiling(a(n-1)^2/a(n-2)), a(0) = 4, a(1) = 14.
Previous Showing 11-12 of 12 results.