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 1-10 of 18 results. Next

A215991 Primes that are the sum of 25 consecutive primes.

Original entry on oeis.org

1259, 1361, 2027, 2267, 2633, 3137, 3389, 4057, 5153, 6257, 6553, 7013, 7451, 7901, 9907, 10499, 10799, 10949, 11579, 12401, 14369, 15013, 15329, 17377, 17903, 18251, 18427, 19309, 22441, 24023, 25057, 25229, 26041, 26699, 28111, 29017, 29207, 30707, 32939, 35051, 36583
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Comments

Such sequences already existed for all odd numbers <= 15. I chose the particular points (in A215991-A216020) so that by referring to a particular n-th term of one of these sequences, the expected range of the n-th term of an x-prime sum can be calculated for any odd x<100000.

Crossrefs

Programs

  • GAP
    P:=Filtered([1..10^4],IsPrime);;
    Filtered(List([0..250],k->Sum([1..25],i->P[i+k])),IsPrime); # Muniru A Asiru, Feb 11 2018
  • Maple
    select(isprime, [seq(add(ithprime(i+k), i=1..25), k=0..250)]); # Muniru A Asiru, Feb 11 2018
  • Mathematica
    Select[ListConvolve[Table[1, 25], Prime[Range[500]]], PrimeQ] (* Jean-François Alcover, Jul 01 2018, after Harvey P. Dale *)
    Select[Total/@Partition[Prime[Range[300]],25,1],PrimeQ] (* Harvey P. Dale, Mar 04 2023 *)
  • PARI
    psumprm(m, n)={my(list=List(), s=sum(j=1,m,prime(j)), i=1); while(#listAndrew Howroyd, Feb 11 2018
    

A070934 Smallest prime equal to the sum of 2n+1 consecutive primes.

Original entry on oeis.org

2, 23, 53, 197, 127, 233, 691, 379, 499, 857, 953, 1151, 1259, 1583, 2099, 2399, 2417, 2579, 2909, 3803, 3821, 4217, 4651, 5107, 5813, 6829, 6079, 6599, 14153, 10091, 8273, 10163, 9521, 12281, 13043, 11597, 12713, 13099, 16763, 15527, 16823, 22741
Offset: 0

Views

Author

Lekraj Beedassy, May 21 2002

Keywords

Examples

			Every term of the increasing sequence of primes 127, 401, 439, 479, 593,... is splittable into a sum of 9 consecutive odd primes and 127 = 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 is the least one corresponding to n = 4.
		

Crossrefs

Cf. Bisection of A070281.
See A082244 for another version.

Programs

  • Mathematica
    f[n_] := Block[{k = 1, s},While[s = Sum[Prime[i], {i, k, k + 2n}]; !PrimeQ[s], k++ ]; s]; Table[f[n], {n, 0, 41}] (* Ray Chandler, Sep 27 2006 *)

Extensions

Corrected and extended by Ray G. Opao, Aug 26 2004
Entry revised by Ray Chandler, Sep 27 2006

A127336 Numbers that are the sum of 9 consecutive primes.

Original entry on oeis.org

100, 127, 155, 187, 221, 253, 287, 323, 363, 401, 439, 479, 515, 553, 593, 635, 679, 721, 763, 803, 841, 881, 929, 977, 1025, 1067, 1115, 1163, 1213, 1267, 1321, 1367, 1415, 1459, 1511, 1555, 1601, 1643, 1691, 1747, 1801, 1851, 1903, 1951, 1999, 2053
Offset: 1

Views

Author

Artur Jasinski, Jan 11 2007

Keywords

Comments

a(n) = absolute value of coefficient of x^8 of the polynomial Product_{j=0..8}(x - prime(n+j)) of degree 9; the roots of this polynomial are prime(n), ..., prime(n+8).

Crossrefs

Programs

  • Magma
    [&+[ NthPrime(n+k): k in [0..8] ]: n in [1..100] ]; // Vincenzo Librandi, Apr 03 2011
    
  • Mathematica
    A127336 = {}; Do[AppendTo[A127336, Sum[Prime[x + n], {n, 0, 8}]], {x, 1, 50}]; A127336 (* Artur Jasinski, Jan 11 2007 *)
    Table[Plus@@Prime[Range[n, n + 8]], {n, 50}] (* Alonso del Arte, Aug 27 2013 *)
    Total/@Partition[Prime[Range[60]],9,1] (* Harvey P. Dale, Nov 18 2020 *)
  • PARI
    {m=46;k=9;for(n=1,m,print1(a=sum(j=0,k-1,prime(n+j)),","))} \\ Klaus Brockhaus, Jan 13 2007
    {m=46;k=9;for(n=1,m,print1(abs(polcoeff(prod(j=0,k-1,(x-prime(n+j))),k-1)),","))} \\ Klaus Brockhaus, Jan 13 2007
    
  • Python
    from sympy import prime
    def a(x): return sum([prime(x + n) for n in range(9)])
    print([a(i) for i in range(1, 50)]) # Indranil Ghosh, Mar 18 2017

Formula

a(n) = A127335(n)+A000040(n+8). - R. J. Mathar, Apr 24 2023

Extensions

Edited by Klaus Brockhaus, Jan 13 2007

A127340 Primes that are the sum of 11 consecutive primes.

Original entry on oeis.org

233, 271, 311, 353, 443, 491, 631, 677, 883, 1367, 1423, 1483, 1543, 1607, 1787, 1901, 1951, 2011, 2141, 2203, 2383, 3253, 3469, 3541, 3617, 3691, 3967, 4159, 4229, 4297, 4943, 5009, 5483, 5657, 5741, 5903, 5981, 6553, 6871, 6991, 7057, 7121, 7187, 7873
Offset: 1

Views

Author

Artur Jasinski, Jan 11 2007

Keywords

Comments

Primes in A127338.
A prime number n is in the sequence if for some k it is the absolute value of coefficient of x^10 of the polynomial Prod_{j=0,10}(x-prime(k+j)); the roots of this polynomial are prime(k), ..., prime(k+10).

Crossrefs

Programs

  • Mathematica
    a = {}; Do[If[PrimeQ[Sum[Prime[x + n], {n, 0, 10}]], AppendTo[a, Sum[Prime[x + n], {n, 0, 10}]]], {x, 1, 500}]; a
    Select[Total/@Partition[Prime[Range[200]],11,1],PrimeQ] (* Harvey P. Dale, Jul 16 2012 *)
  • PARI
    {m=125;k=11;for(n=0,m-1,a=sum(j=1,k,prime(n+j));if(isprime(a),print1(a,",")))} \\ Klaus Brockhaus, Jan 13 2007
    
  • PARI
    {m=126;k=11;for(n=1,m,a=abs(polcoeff(prod(j=0,k-1,(x-prime(n+j))),k-1));if(isprime(a),print1(a,",")))} \\ Klaus Brockhaus, Jan 13 2007

Extensions

Edited by Klaus Brockhaus, Jan 13 2007

A127341 Primes that can be written as the sum of 13 consecutive primes.

Original entry on oeis.org

691, 863, 983, 1153, 1283, 1553, 1621, 1753, 1823, 2111, 2239, 2311, 2963, 3191, 3617, 3853, 4099, 4357, 4519, 4597, 4999, 5081, 5393, 5471, 5623, 5693, 5849, 6229, 6491, 6971, 7349, 7673, 8123, 8191, 8669, 8933, 9391, 10141, 10499, 10949, 11273
Offset: 1

Views

Author

Artur Jasinski, Jan 11 2007

Keywords

Examples

			691 = prime(10) + prime(11) + ... + prime(22) = 29 + 31 + ... + 79.
		

Crossrefs

Programs

  • Mathematica
    Select[Table[Sum[Prime[i], {i, n, n + 12}], {n, 1, 150}], PrimeQ[ # ] &]
    Select[Total/@Partition[Prime[Range[200]],13,1],PrimeQ] (* Harvey P. Dale, Aug 13 2021 *)

Extensions

Edited by Stefan Steinerberger, Jul 31 2007

A127346 Primes in A127345.

Original entry on oeis.org

31, 71, 167, 311, 1151, 3119, 4871, 5711, 6791, 14831, 24071, 33911, 60167, 79031, 101159, 106367, 115631, 158231, 235751, 259751, 366791, 402551, 455471, 565919, 635711, 644951, 1124831, 1347971, 1510799, 1547927, 1743419, 1851671, 2048471
Offset: 1

Views

Author

Artur Jasinski, Jan 11 2007

Keywords

Comments

Primes of the form prime(k)*prime(k+1) + prime(k)*prime(k+2) + prime(k+1)*prime(k+2).
A prime number n is in the sequence if for some k it is the coefficient of x^1 of the polynomial Product_{j=0..2} (x-prime(k+j)); the roots of this polynomial are prime(k), ..., prime(k+2).

Crossrefs

Programs

  • Mathematica
    b = {}; a = {}; Do[If[PrimeQ[Prime[x] Prime[x + 1] + Prime[x] Prime[x + 2] + Prime[x + 1] Prime[x + 2]], AppendTo[a, Prime[x] Prime[x + 1] + Prime[x] Prime[x + 2] + Prime[x + 1] Prime[x + 2]], AppendTo[b, Prime[x] Prime[x + 1] + Prime[x] Prime[x + 2] + Prime[x + 1] Prime[x + 2]]], {x, 1, 100}]; Print[a] (* Artur Jasinski, Jan 11 2007 *)
    s[li_] := li[[1]]*(li[[2]]+li[[3]])+li[[2]]*li[[3]]; Select[(s[#]&/@Partition[Prime[Range[100]], 3, 1]), PrimeQ] (* Zak Seidov, Jan 13 2012 *)
  • PARI
    {m=143;k=2;for(n=1,m,a=sum(i=n,n+k-1,sum(j=i+1,n+k,prime(i)*prime(j)));if(isprime(a),print1(a,",")))} \\ Klaus Brockhaus, Jan 21 2007
    
  • PARI
    {m=143;k=2;for(n=1,m,a=polcoeff(prod(j=0,k,(x-prime(n+j))),1);if(isprime(a),print1(a,",")))} \\ Klaus Brockhaus, Jan 21 2007
    
  • PARI
    p=2; q=3; forprime(r=5, 1e3, if(isprime(t=p*q+p*r+q*r), print1(t", ")); p=q; q=r) \\ Charles R Greathouse IV, Jan 13 2012

Formula

a(n) = A127345(A204231(n)). - Zak Seidov, Jan 13 2012

Extensions

Edited and extended by Klaus Brockhaus, Jan 21 2007

A082244 Smallest odd prime that is the sum of 2n+1 consecutive primes.

Original entry on oeis.org

3, 23, 53, 197, 127, 233, 691, 379, 499, 857, 953, 1151, 1259, 1583, 2099, 2399, 2417, 2579, 2909, 3803, 3821, 4217, 4651, 5107, 5813, 6829, 6079, 6599, 14153, 10091, 8273, 10163, 9521, 12281, 13043, 11597, 12713, 13099, 16763, 15527, 16823, 22741
Offset: 0

Views

Author

Cino Hilliard, May 09 2003

Keywords

Examples

			For n = 2,
2+3+5+7+11=28
3+5+7+11+13=39
5+7+11+13+17=53
so 53 is the first prime that is the sum of 5 consecutive primes
		

Crossrefs

See A070934 for another version.

Programs

  • Maple
    P:= select(isprime, [seq(i,i=3..3000,2)]):
    S:= [0,op(ListTools:-PartialSums(P))]: nS:= nops(S):
    R:= NULL:
    for n from 1 do
      found:= false;
      for j from 1 to nS - 2*n + 1 while not found do
        v:= S[j+2*n-1]-S[j];
        if isprime(v) then R:= R,v; found:= true fi
      od;
      if not found then break fi;
    od:
    R; # Robert Israel, Jan 09 2025
  • Mathematica
    Join[{3},Table[SelectFirst[Total/@Partition[Prime[Range[1000]],2n+1,1],PrimeQ],{n,50}]] (* Requires Mathematica version 10 or later *) (* Harvey P. Dale, Sep 15 2016 *)
  • PARI
    \\ First prime that the sum of an odd number of consecutive primes
    psumprm(n) = { sr=0; forstep(i=1,n,2, s=0; for(j=1,i, s+=prime(j); ); for(x=1,n, s = s - prime(x)+ prime(x+i); if(isprime(s),sr+=1.0/s; print1(s" "); break); ); ); print(); print(sr) }

Formula

The sum of the reciprocals = 0.4304...

A082252 Concatenation of (3n-2), (3n-1) and 3n divided by 3.

Original entry on oeis.org

41, 152, 263, 33704, 43805, 53906, 64007, 74108, 84209, 94310, 104411, 114512, 124613, 134714, 144815, 154916, 165017, 175118, 185219, 195320, 205421, 215522, 225623, 235724, 245825, 255926, 266027, 276128, 286229, 296330, 306431, 316532, 326633, 33367034
Offset: 1

Views

Author

Amarnath Murthy, Apr 11 2003

Keywords

Examples

			a(5) = 131415/3 = 43805.
		

Crossrefs

Programs

  • PARI
    a(n)={fromdigits(concat([digits(3*n-2), digits(3*n-1), digits(3*n)]))/3} \\ Andrew Howroyd, Nov 09 2019

Extensions

Terms a(12) and beyond from Andrew Howroyd, Nov 09 2019

A082253 Concatenation of (5n-4), (5n-3), (5n-2), (5n-1) and 5n divided by 5.

Original entry on oeis.org

2469, 135782, 222426283, 323436384, 424446485, 525456586, 626466687, 727476788, 828486889, 929496990, 1030507091, 1131517192, 1232527293, 1333537394, 1434547495, 1535557596, 1636567697, 1737577798, 1838587899, 19395979820, 20220420620821, 21221421621822
Offset: 1

Views

Author

Amarnath Murthy, Apr 11 2003

Keywords

Examples

			a(3) = 1112131415/5 = 222426283.
		

Crossrefs

Programs

  • PARI
    a(n)={fromdigits(concat(vector(5, k, digits(5*(n-1)+k))))/5} \\ Andrew Howroyd, Nov 09 2019

Extensions

Terms a(12) and beyond from Andrew Howroyd, Nov 09 2019

A082254 Concatenation of (6n-5), (6n-4), (6n-3), (6n-2), (6n-1) and 6n divided by 6.

Original entry on oeis.org

20576, 131516852, 21902526953, 32003537054, 42104547155, 52205557256, 62306567357, 72407577458, 82508587559, 92609597660, 102710607761, 112811617862, 122912627963, 133013638064, 143114648165, 153215658266, 163316516683517, 17184017517684518, 18185018518685519
Offset: 1

Views

Author

Amarnath Murthy, Apr 11 2003

Keywords

Examples

			a(3) = 131415161718/6 = 21902526953.
		

Crossrefs

Programs

  • PARI
    a(n)={fromdigits(concat(vector(6, k, digits(6*(n-1)+k))))/6} \\ Andrew Howroyd, Nov 09 2019

Extensions

Terms a(8) and beyond from Andrew Howroyd, Nov 09 2019
Showing 1-10 of 18 results. Next