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 1-4 of 4 results.

A095278 Numbers k such that 4k + 3 is prime.

Original entry on oeis.org

0, 1, 2, 4, 5, 7, 10, 11, 14, 16, 17, 19, 20, 25, 26, 31, 32, 34, 37, 40, 41, 44, 47, 49, 52, 55, 56, 59, 62, 65, 67, 70, 76, 77, 82, 86, 89, 91, 94, 95, 104, 107, 109, 110, 115, 116, 119, 121, 122, 124, 125, 130, 136, 140, 142, 146, 149, 151, 154, 157, 160, 161, 164
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Cf. A002145. Complement of A095277. Union of A095272 and A095273. Cf. also A005098.

Programs

Formula

a(n) = (A002145(n) - 3)/4.

A095103 4k+3 primes whose Legendre-vector is not valid Dyck-path.

Original entry on oeis.org

19, 43, 67, 107, 127, 139, 163, 179, 211, 223, 227, 283, 307, 331, 347, 367, 379, 443, 463, 467, 487, 491, 499, 523, 547, 571, 587, 619, 631, 643, 683, 691, 727, 739, 787, 811, 823, 827, 859, 883, 907, 947, 967, 1019, 1051, 1087, 1123, 1163
Offset: 1

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Intersection of A000040 and A095101. Complement of A095102 in A002145.
Cf. A095093, A095108 (diving indices).

Programs

  • Mathematica
    L = {}; Do[p = Prime[k]; If[Mod[p, 4] == 3 && Min[Table[Sum[JacobiSymbol[n, p], {n, 0, m}], {m, 0, p - 1}]] < 0, L = Append[L, p]], {k, 1, 192}]; L (* From Jonathan Sondow, Oct 25 2011 *)
  • PARI
    isok(m) = {my(s=0); if(m%4==3&&isprime(m), for(i=1, m-1, if((s+=kronecker(i, m))<0, return(1)))); 0; } \\ Jinyuan Wang, Jul 20 2020
    
  • Sage
    def A095103_list(n) :
        def is_Motzkin(n, k):
            s = 0
            for i in (1..k) :
                s += jacobi_symbol(i, n)
                if s < 0 : return false
            return true
        P = filter(is_prime, range(n+1)[3::4])
        return filter(lambda m: not is_Motzkin(m, m//2), P)
    A095103_list(1163) # Peter Luschny, Aug 08 2012

Formula

a(n) = 4*A095273(n) + 3.

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.

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

Views

Author

Antti Karttunen, Jun 01 2004

Keywords

Crossrefs

Cf. A095101. Complement of A095274. Subset: A095273.
Showing 1-4 of 4 results.