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.

A285096 Primes with integer arithmetic mean of digits = 2 in base 10.

Original entry on oeis.org

2, 13, 31, 1061, 1151, 1223, 1511, 1601, 2141, 2213, 2411, 3023, 3041, 3203, 3221, 4013, 4211, 5003, 5021, 6011, 6101, 7001, 10009, 10243, 10333, 10513, 10531, 10711, 11071, 11161, 11251, 11503, 11701, 12007, 12043, 12241, 12421, 12511, 12601, 13033, 13411
Offset: 1

Views

Author

Jaroslav Krizek, Apr 16 2017

Keywords

Crossrefs

Primes in A061385. Subsequence of A069709.
Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), this sequence (k = 2), A285225 (k = 4), A285226 (k = 5), A285227 (k = 7), A285228 (k = 8).

Programs

  • Magma
    [n: n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0 and &+Intseq(n) / #Intseq(n) eq 2];
  • Maple
    S:= proc(d,k,flag) option remember;
      if d = 1 then
        if k >= 0 and k <= 9 then return [k]
        else return []
        fi
      fi;
      [seq(op(map(`+`, procname(d-1,k-i,0), i*10^(d-1))),i=flag..min(k,9))]
    end proc:
    seq(op(select(isprime,S(d,2*d,1))),d=1..5);# Robert Israel, Apr 23 2017
  • Mathematica
    Select[Prime[Range[1600]],Mean[IntegerDigits[#]]==2&] (* Harvey P. Dale, Aug 07 2021 *)

A285225 Primes with integer arithmetic mean of digits = 4 in base 10.

Original entry on oeis.org

17, 53, 71, 1069, 1087, 1249, 1429, 1447, 1483, 1609, 1627, 1663, 1753, 1861, 1933, 1951, 2239, 2293, 2347, 2383, 2437, 2473, 2617, 2671, 2707, 2833, 2851, 3049, 3067, 3229, 3319, 3373, 3391, 3463, 3517, 3571, 3607, 3643, 3733, 3823, 3931, 4057, 4093, 4129
Offset: 1

Views

Author

Jaroslav Krizek, Apr 16 2017

Keywords

Crossrefs

Primes in A061387. Subsequence of A069709.
Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), A285096 (k = 2), this sequence (k = 4), A285226 (k = 5), A285227 (k = 7), A285228 (k = 8).

Programs

  • Magma
    [n: n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0 and &+Intseq(n) / #Intseq(n) eq 4];
  • Mathematica
    Select[Prime[Range[600]],Mean[IntegerDigits[#]]==4&] (* Harvey P. Dale, Jun 11 2024 *)

A285227 Primes with integer arithmetic mean of digits = 7 in base 10.

Original entry on oeis.org

7, 59, 1999, 3889, 4789, 4969, 4987, 5689, 5779, 5869, 6679, 6949, 6967, 7489, 7669, 7687, 7759, 7867, 7993, 8389, 8677, 8839, 8893, 8929, 9199, 9397, 9649, 9739, 9829, 9883, 9973, 18899, 19889, 19979, 19997, 28979, 29789, 29879, 35999, 36899, 37799, 37889
Offset: 1

Views

Author

Jaroslav Krizek, Apr 19 2017

Keywords

Crossrefs

Primes from A061424. Subsequence of A069709.
Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), A285096 (k = 2), A285225 (k = 4), A285226 (k = 5), this sequence (k = 7), A285228 (k = 8).

Programs

  • Magma
    [n: n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0 and &+Intseq(n) / #Intseq(n) eq 7]
    
  • Mathematica
    Select[Prime@ Range@ PrimePi@ 40000, Mean@ IntegerDigits@ # == 7 &] (* Michael De Vlieger, Apr 22 2017 *)
  • Python
    from itertools import count, islice
    from collections import Counter
    from sympy.utilities.iterables import partitions, multiset_permutations
    from sympy import isprime
    def A285227_gen(): # generator of terms
        yield 7
        for l in count(2):
            for i in range(1,10):
                yield from sorted(q for q in (int(str(i)+''.join(map(str,j))) for s,p in partitions(7*l-i,m=l-1,k=9,size=True) for j in multiset_permutations([0]*(l-1-s)+list(Counter(p).elements()))) if isprime(q))
    A285227_list = list(islice(A285227_gen(),30)) # Chai Wah Wu, Nov 29 2023

A285228 Primes with integer arithmetic mean of digits = 8 in base 10.

Original entry on oeis.org

79, 97, 6899, 8699, 8969, 9689, 9887, 49999, 68899, 69997, 77899, 78889, 78979, 79699, 79987, 85999, 88789, 88897, 88969, 89599, 89689, 89779, 89797, 89959, 89977, 94999, 95989, 96799, 96979, 96997, 97789, 97879, 97987, 98689, 98779, 98869, 98887, 99679, 99787
Offset: 1

Views

Author

Jaroslav Krizek, Apr 19 2017

Keywords

Crossrefs

Primes from A061425. Subsequence of A069709.
Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), A285096 (k = 2), A285225 (k = 4), A285226 (k = 5), A285227 (k = 7), this sequence (k = 8).

Programs

  • Magma
    [n: n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0 and &+Intseq(n) / #Intseq(n) eq 8];
    
  • Mathematica
    Select[Prime@ Range@ PrimePi[10^5], Mean@ IntegerDigits@ # == 8 &] (* Michael De Vlieger, Apr 22 2017 *)
  • Python
    from itertools import count, islice
    from collections import Counter
    from sympy.utilities.iterables import partitions, multiset_permutations
    def A285228_gen(): # generator of terms
        for l in count(2):
            for i in range(1,10):
                yield from sorted(q for q in (int(str(i)+''.join(map(str,j))) for s,p in partitions((l<<3)-i,m=l-1,k=9,size=True) for j in multiset_permutations([0]*(l-1-s)+list(Counter(p).elements()))) if isprime(q))
    A285228_list = list(islice(A285228_gen(),30)) # Chai Wah Wu, Nov 28 2023

A285095 Corresponding values of arithmetic means of digits of primes from A069709.

Original entry on oeis.org

2, 3, 5, 7, 1, 2, 4, 5, 2, 5, 4, 7, 4, 5, 8, 8, 1, 2, 4, 4, 2, 1, 2, 4, 5, 4, 4, 4, 5, 2, 5, 2, 4, 4, 4, 5, 4, 5, 4, 4, 4, 5, 7, 1, 5, 2, 2, 4, 4, 5, 4, 4, 2, 4, 5, 4, 5, 5, 4, 5, 4, 5, 4, 5, 5, 4, 5, 4, 5, 5, 5, 1, 2, 2, 4, 4, 5, 2, 2, 4, 4, 5, 4, 4, 5, 4, 5
Offset: 1

Views

Author

Jaroslav Krizek, Apr 16 2017

Keywords

Crossrefs

Cf. A069709 (primes with integer arithmetic mean of digits in base 10).
Sequences of primes such that a(n) = k for k = 1, 2, 4, 5, 7 and 8: A069710 (k = 1), A285096 (k = 2), A285225 (k = 4), A285226 (k = 5), A285227 (k = 7), A285228 (k = 8).

Programs

  • Magma
    [&+Intseq(n) / #Intseq(n): n in [1..100000] | IsPrime(n) and &+Intseq(n) mod #Intseq(n) eq 0];
Showing 1-5 of 5 results.