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 1-5 of 5 results.

A138836 Non-Mersenne numbers A001348.

Original entry on oeis.org

1, 2, 4, 5, 6, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70
Offset: 1

Views

Author

Omar E. Pol, Apr 05 2008

Keywords

Comments

Numbers that are not in A001348.
a(1) to a(2042) equals A133398, then a(2043)=2048 <> A133398(2043)=2047.

Links

Crossrefs

Cf. A001348, A001690, A062289, A133398, A138837, A138888, A138890, A138891. A133398.

Programs

  • Python
    from sympy import primepi, prime
def A138836(n): return n+(k:=int(primepi((n).bit_length())-1))+int(n+k+1>=1<1 else 1 # Chai Wah Wu, Sep 10 2024

A138890 Non-Padovan numbers.

Original entry on oeis.org

6, 8, 10, 11, 13, 14, 15, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 29, 30, 31, 32, 33, 34, 35, 36, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 66, 67, 68, 69, 70, 71, 72, 73, 74
Offset: 1

Views

Author

Omar E. Pol, Apr 05 2008

Keywords

Comments

Natural numbers that are not in the Padovan sequence A000931.

Links

Crossrefs

Cf. A000931, A001690, A062289, A092460, A134816, A138836, A138888, A138891.

Programs

  • Mathematica
    Complement[Range[0, Max[#]], #] &@ Union@ LinearRecurrence[{0, 1, 1}, {1, 0, 0}, 23] (* Michael De Vlieger, Sep 17 2024 *)
  • Python
    def A138890(n):
    def f(x):
        if x<=1: return n+1
        a, b, c, d = 1, 1, 1, 0
        while c<=x:
            a, b, c = b, c, a+b
            d += 1
        return n+d-1
    m, k = n, f(n)
    while m != k: m, k = k, f(k)
    return m # Chai Wah Wu, Sep 10 2024

A138889 Primes that are not Fermat primes.

Original entry on oeis.org

2, 7, 11, 13, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 263, 269, 271, 277, 281, 283
Offset: 1

Views

Author

Omar E. Pol, Apr 03 2008

Keywords

Comments

Primes that are not members of A019434.

Crossrefs

Cf. A000040, A000217, A019434, A138837, A138888.

A138891 Non-Motzkin numbers.

Original entry on oeis.org

0, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76
Offset: 1

Views

Author

Omar E. Pol, Apr 05 2008

Keywords

Comments

Nonnegative integers that are not in A001006.

Crossrefs

Cf. A001006, A001690, A062289, A092460, A138836, A138888, A138890.

A138887 Numbers that are not Sophie Germain primes.

Original entry on oeis.org

0, 1, 4, 6, 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 24, 25, 26, 27, 28, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68
Offset: 0

Views

Author

Omar E. Pol, Apr 05 2008

Keywords

Comments

Nonnegative integers that are not in A005384.
A156660(a(n)) = 0; A053176 is a subsequence. [From Reinhard Zumkeller, Feb 18 2009]

Crossrefs

Cf. A001690, A005384, A053176, A062289, A138888, A138889, A138890, A138891.
Showing 1-5 of 5 results.

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