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.

A079848 Smallest primes such that a(j) - a(k) are all different.

Original entry on oeis.org

2, 3, 5, 11, 23, 37, 47, 97, 101, 149, 211, 233, 353, 383, 487, 641, 757, 797, 919, 1097, 1163, 1381, 1409, 1481, 1777, 1997, 2287, 2417, 2969, 3049, 3371, 3529, 3929, 4231, 4759, 5279, 5449, 5717, 5953, 6529, 6983, 7583, 8053, 8819, 9043, 10133, 10799
Offset: 1

Views

Author

Amarnath Murthy, Feb 18 2003

Keywords

Comments

This is the slowest-growing prime B2 sequence. See A005282. - T. D. Noe, Mar 24 2007

Crossrefs

Cf. A079849.

Programs

  • Mathematica
    terms = 100; a = Table[0, {terms}]; s={}; k=0; A079848list = Reap[For[p=2, p < 10^5, p = NextPrime[p], j=1; While[j <= k && FreeQ[s, p-a[[j]]], j++]; If[j>k, For[j=1, j <= k, j++, s = Union[s, {p-a[[j]]}]]; k++; a[[k]] = p; Print[p]; Sow[p]; If[k == terms, Break[]]]]][[2, 1]]; (* Jean-François Alcover, Nov 02 2016, adapted from Max Alekseyev's PARI code *)
  • PARI
    a=vector(100);s=Set();k=0;forprime(p=2,10^5,j=1;while(j<=k&&!setsearch(s,p-a[j]),j++);if(j>k, for(j=1,k,s=setunion(s,[p-a[j]]));k++;a[k]=p;print1(" ",p);if(k==100,break))) \\ Max Alekseyev, Feb 14 2005
    
  • Python
    from itertools import count, islice
    from sympy import nextprime
    def A079848_gen(): # generator of terms
        aset2, alist, k = set(), [], 0
        while (k:=nextprime(k)):
            bset2 = set()
            for a in alist:
                if (b:=k-a) in aset2:
                    break
                bset2.add(b)
            else:
                yield k
                alist.append(k)
                aset2.update(bset2)
    A079848_list = list(islice(A079848_gen(),30)) # Chai Wah Wu, Sep 11 2023

Extensions

More terms from Max Alekseyev, Feb 14 2005