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.

A095065 Number of fib000 primes (A095085) in range ]2^n,2^(n+1)].

Original entry on oeis.org

0, 1, 1, 1, 1, 4, 9, 6, 19, 28, 54, 109, 210, 373, 707, 1316, 2497, 4827, 9127, 17467, 33212, 63161, 121404, 232455, 446846, 860466, 1658020, 3200462, 6184814, 11971998, 23184215, 44934259, 87179855, 169330402, 329113635
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Formula

a(n) = A095062(n) - A095068(n).

Extensions

a(34)-a(35) from Amiram Eldar, Jun 13 2024

A101345 a(n) = Knuth's Fibonacci (or circle) product "2 o n".

Original entry on oeis.org

5, 8, 13, 18, 21, 26, 29, 34, 39, 42, 47, 52, 55, 60, 63, 68, 73, 76, 81, 84, 89, 94, 97, 102, 107, 110, 115, 118, 123, 128, 131, 136, 141, 144, 149, 152, 157, 162, 165, 170, 173, 178, 183, 186, 191, 196, 199, 204, 207, 212, 217, 220, 225, 228, 233, 238, 241, 246
Offset: 1

Views

Author

N. J. A. Sloane, Jan 26 2005

Keywords

Comments

Numbers whose Zeckendorf representation ends with 000. - Benoit Cloitre, Jan 11 2014
The asymptotic density of this sequence is sqrt(5)-2. - Amiram Eldar, Mar 21 2022

Crossrefs

Second row of array in A101330.
Set-wise difference of A026274 - A035337.

Programs

Formula

a(n) = floor(phi^3*(n+1)) - 3 - floor(2*phi*(n+1)) + 2*floor(phi*(n+1)) where phi = (1+sqrt(5))/2. - Benoit Cloitre, Jan 11 2014
a(n) = 2*A000201(n+1) + n - 2. See the comments in A101642. - Michel Dekking, Dec 23 2019

Extensions

More terms from David Applegate, Jan 26 2005
More terms from Robert G. Wilson v, Feb 04 2005

A095082 Fib00 primes, i.e., primes p whose Zeckendorf-expansion A014417(p) ends with two zeros.

Original entry on oeis.org

3, 5, 11, 13, 29, 37, 47, 71, 73, 79, 89, 97, 107, 113, 131, 139, 149, 157, 173, 181, 191, 199, 223, 233, 241, 251, 257, 283, 293, 317, 359, 367, 401, 409, 419, 443, 461, 479, 487, 503, 521, 547, 563, 571, 587, 613, 631, 647, 673, 683, 691, 733
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Cf. A095062. Intersection of A000040 and A026274. Union of A095085 and A095088.

Programs

  • PARI
    list(lim)=my(v=List(), w=quadgen(20), phi=(1+w)/2, p2=phi^2, x=(2*phi-2)*p2, q);  lim=lim\1+1; while(xCharles R Greathouse IV, Nov 10 2021
  • Python
    from sympy import fibonacci, primerange
    def a(n):
        k=0
        x=0
        while n>0:
            k=0
            while fibonacci(k)<=n: k+=1
            x+=10**(k - 3)
            n-=fibonacci(k - 1)
        return x
    def ok(n): return str(a(n))[-2:]=="00"
    print([n for n in primerange(1, 1001) if ok(n)]) # Indranil Ghosh, Jun 08 2017
    
Showing 1-3 of 3 results.