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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A095104 Diving index of the n-th 4k+3 prime (A002145(n)).

Original entry on oeis.org

0, 0, 0, 3, 0, 0, 3, 0, 0, 3, 0, 0, 0, 0, 7, 7, 0, 3, 0, 3, 0, 11, 0, 0, 3, 13, 61, 0, 0, 0, 0, 3, 3, 0, 3, 7, 0, 45, 3, 0, 0, 0, 0, 7, 7, 35, 0, 7, 35, 3, 0, 3, 3, 0, 3, 15, 0, 0, 3, 15, 3, 0, 0, 7, 3, 0, 45, 3, 0, 0, 3, 3, 7, 7, 0, 3, 0, 3, 0, 3, 0, 0, 7, 7, 0, 0, 0, 67, 0, 0, 3, 0
Offset: 1

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Author

Antti Karttunen, Jun 01 2004

Keywords

Comments

Diving index of an odd number n is the first integer u > 1 where Sum_{i=1..u} J(i/n) results -1 and zero if never. Here J(i/n) is Jacobi symbol of i and n, which reduces to a Legendre symbol L(i/n) when n is a prime.

Crossrefs

a(n)=A095105(n)+1 modulo A002145(n). Cf. A095106, A095108 (same sequence with zeros removed), A095269.

A095105 Length of maximal Dyck path prefix in the Legendre-vector of the n-th 4k+3 prime (A002145(n)).

Original entry on oeis.org

2, 6, 10, 2, 22, 30, 2, 46, 58, 2, 70, 78, 82, 102, 6, 6, 130, 2, 150, 2, 166, 10, 190, 198, 2, 12, 60, 238, 250, 262, 270, 2, 2, 310, 2, 6, 358, 44, 2, 382, 418, 430, 438, 6, 6, 34, 478, 6, 34, 2, 502, 2, 2, 562, 2, 14, 598, 606, 2, 14, 2, 646, 658, 6, 2, 718
Offset: 1

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Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

a(n)=A095104(n)-1 modulo A002145(n). Cf. A095107, A095270.

A095106 Sum of diving indices of all 4k+3 primes in range ]2^n,2^(n+1)].

Original entry on oeis.org

0, 0, 0, 3, 3, 17, 94, 158, 213, 571, 1987, 3163, 27993, 45176, 205432, 707079, 2319521, 7603409, 25967812, 83981455, 310267532
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

A095107 Sum of maximal Dyck path prefix lengths of all 4k+3 primes in range ]2^n,2^(n+1)].

Original entry on oeis.org

2, 6, 10, 54, 106, 346, 1410, 3994, 12828, 46242, 158252, 542568, 1865796, 6822592, 25120772, 88926198, 327561126, 1212380122, 4358259840, 16111686770, 59936356888
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

A095270 Length of maximal Motzkin path prefix in the Jacobi-vector of 4n+3.

Original entry on oeis.org

2, 6, 10, 14, 2, 22, 26, 30, 34, 38, 2, 46, 9, 54, 58, 62, 2, 70, 74, 78, 82, 86, 2, 94, 9, 102, 6, 110, 2, 118, 6, 6, 130, 134, 2, 142, 7, 150, 7, 158, 2, 166, 170, 174, 10, 182, 2, 190, 33, 198, 7, 18, 2, 214, 9, 12, 60, 230, 2, 238, 242, 6, 250, 254, 2, 262
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Formula

a(n) = A095269(n)-1 modulo A004767(n).

A095272 a(n) = (A095102(n)-3)/4.

Original entry on oeis.org

0, 1, 2, 5, 7, 11, 14, 17, 19, 20, 25, 32, 37, 41, 47, 49, 59, 62, 65, 67, 77, 89, 95, 104, 107, 109, 119, 125, 140, 149, 151, 161, 164, 179, 185, 187, 209, 215, 221, 227, 229, 242, 245, 247, 257, 259, 265, 272, 275, 287, 305, 307, 319, 329, 349
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Complement of A095273 in A095278, subset of A095274.

A095273 a(n) = (A095103(n)-3)/4.

Original entry on oeis.org

4, 10, 16, 26, 31, 34, 40, 44, 52, 55, 56, 70, 76, 82, 86, 91, 94, 110, 115, 116, 121, 122, 124, 130, 136, 142, 146, 154, 157, 160, 170, 172, 181, 184, 196, 202, 205, 206, 214, 220, 226, 236, 241, 254, 262, 271, 280, 290, 292, 296, 314, 320, 322
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Complement of A095272 in A095278, subset of A095275.

A095275 a(n) = (A095101(n)-3)/4.

Original entry on oeis.org

4, 10, 12, 16, 22, 24, 26, 28, 30, 31, 34, 36, 38, 40, 44, 46, 48, 50, 51, 52, 54, 55, 56, 58, 61, 64, 66, 68, 70, 72, 76, 78, 80, 82, 84, 86, 88, 91, 94, 96, 100, 102, 105, 106, 108, 110, 112, 114, 115, 116, 118, 120, 121, 122, 124, 126, 128, 130, 132
Offset: 0

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Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Cf. A095101. Complement of A095274. Subset: A095273.

A095280 Lower Wythoff primes, i.e., primes in A000201.

Original entry on oeis.org

3, 11, 17, 19, 29, 37, 43, 53, 59, 61, 67, 71, 79, 97, 101, 103, 113, 127, 131, 137, 139, 163, 173, 179, 181, 197, 199, 211, 223, 229, 239, 241, 257, 263, 271, 281, 283, 307, 313, 317, 331, 347, 349, 359, 367, 373, 383, 389, 401, 409, 419, 433
Offset: 1

Views

Author

Antti Karttunen, Jun 04 2004

Keywords

Comments

Contains all primes p whose Zeckendorf-expansion A014417(p) ends with an even number of 0's.
For generalizations and conjectures, see A184774.

Crossrefs

Intersection of A000040 & A000201. Complement of A095281 in A000040. Cf. A095080, A095083, A095084, A095290, A184792, A184793, A184794, A184796.

Programs

  • Maple
    R:= NULL: count:= 0:
    for n from 1 while count < 100 do
      p:= floor(n*phi);
      if isprime(p) then R:= R,p; count:= count+1 fi
    od:
    R; # Robert Israel, Jan 17 2023
  • Mathematica
    (See A184792.)
  • Python
    from math import isqrt
    from itertools import count, islice
    from sympy import isprime
    def A095280_gen(): # generator of terms
        return filter(isprime,((n+isqrt(5*n**2)>>1) for n in count(1)))
    A095280_list = list(islice(A095280_gen(),30)) # Chai Wah Wu, Aug 16 2022

A095282 Primes whose binary-expansion ends with an even number of 1's.

Original entry on oeis.org

2, 3, 11, 19, 43, 47, 59, 67, 79, 83, 107, 131, 139, 163, 179, 191, 211, 227, 239, 251, 271, 283, 307, 331, 347, 367, 379, 419, 431, 443, 463, 467, 491, 499, 523, 547, 563, 571, 587, 619, 643, 659, 683, 691, 719, 739, 751, 787, 811, 827, 859
Offset: 1

Views

Author

Antti Karttunen, Jun 04 2004

Keywords

Crossrefs

Intersection of A000040 & (complement of A079523). Complement of A095283 in A000040. Cf. A027699, A095292.

Programs

  • Maple
    q:= proc(n) local i, l, r; l, r:= convert(n, base, 2), 0;
          for i to nops(l) while l[i]=1 do r:=r+1 od; is(r, even)
        end:
    select(q, [ithprime(i)$i=1..200])[];  # Alois P. Heinz, Dec 15 2019
  • Mathematica
    been1Q[n_]:=Module[{c=Split[IntegerDigits[n,2]][[-1]]},c[[1]]==1&&EvenQ[ Length[ c]]]; Join[{2},Select[Prime[Range[150]],been1Q]] (* Harvey P. Dale, Dec 14 2019 *)
  • PARI
    is(n)=valuation(n+1,2)%2==0 && isprime(n) \\ Charles R Greathouse IV, Oct 09 2013
Previous Showing 51-60 of 143 results. Next