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 32 results. Next

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

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...

A342439 Let S(n,k) denote the set of primes < 10^n which are the sum of k consecutive primes, and let K = maximum k >= 2 such that S(n,k) is nonempty; then a(n) = max S(n,K).

Original entry on oeis.org

5, 41, 953, 9521, 92951, 997651, 9964597, 99819619, 999715711, 9999419621, 99987684473, 999973156643, 9999946325147, 99999863884699, 999999149973119, 9999994503821977, 99999999469565483, 999999988375776737, 9999999776402081701
Offset: 1

Views

Author

Bernard Schott, Mar 12 2021

Keywords

Comments

Inspired by the 50th problem of Project Euler (see link).
There must be at least two consecutive primes in the sum.
The corresponding number K of consecutive primes to get this largest prime is A342440(n) and the first prime of these A342440(n) consecutive primes is A342453(n).
It can happen that the sums of K = A342440(n) consecutive primes give two (or more) distinct n-digit primes. In that case, a(n) is the greatest of these primes. Martin Ehrenstein proved that there are only two such cases when 1 <= n <= 19, for n = 7 and n = 15 (see corresponding examples).
Solutions and Python program are proposed in Dreamshire and Archive.today links. - Daniel Suteu, Mar 12 2021

Examples

			a(1) = 5 = 2+3.
a(2) = 41 = 2 + 3 + 5 + 7 + 11 + 13; note that 97 = 29 + 31 + 37 is prime, sum of 3 consecutive primes, but 41 is obtained by adding 6 consecutive primes, so, 97 is not a term.
A342440(7) = 1587, and there exist two 7-digit primes that are sum of 1587 consecutive primes; as 9951191 = 5+...+13399 < 9964597 = 7+...+13411 hence a(7) = 9964597.
A342440(15) = 10695879 , and there exist two 15-digit primes that are sum of 10695879 consecutive primes; as 999998764608469 = 7+...+192682309 < 999999149973119 = 13+...+192682337, hence a(15) = 999999149973119.
		

Crossrefs

Extensions

Name improved by N. J. A. Sloane, Mar 12 2021
a(4)-a(17) from Daniel Suteu, Mar 12 2021
a(18)-a(19) from Martin Ehrenstein, Mar 13 2021
a(7) and a(15) corrected by Martin Ehrenstein, Mar 15 2021

A216020 Primes that are the sum of 100001 consecutive primes.

Original entry on oeis.org

62308795099, 62312695301, 62332197553, 62349100789, 62356902719, 62371207153, 62423231159, 62425832657, 62457052223, 62458353173, 62459654141, 62464858003, 62479168853, 62483071967, 62499986407, 62502588679, 62507793281, 62510395583, 62512997927, 62526009929
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

Programs

  • Mathematica
    Select[Total/@Partition[Prime[Range[120000]],100001,1],PrimeQ] (* Harvey P. Dale, Jun 06 2018 *)

Extensions

More terms added from b-file by Andrew Howroyd, Feb 19 2018

A215992 Primes that are the sum of 51 consecutive primes.

Original entry on oeis.org

6829, 7853, 9473, 10037, 10601, 12041, 12329, 12917, 13217, 13523, 14713, 16493, 17099, 21179, 21503, 23459, 24091, 24419, 26321, 29243, 29567, 30223, 30881, 32237, 32939, 33623, 33961, 34301, 34651, 35677, 36013, 36997, 42221, 44371, 44729
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

A215993 Primes that are the sum of 101 consecutive primes.

Original entry on oeis.org

37447, 38047, 44203, 48611, 49253, 60259, 60923, 68281, 74297, 82421, 84503, 86599, 91423, 92831, 99761, 108533, 120811, 125887, 126613, 128761, 129469, 133781, 134507, 138863, 139591, 150827, 159161, 160697, 163003, 164531, 170633, 173741, 175277, 176797
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

Programs

  • Mathematica
    Select[Total/@Partition[Prime[Range[1000]],101,1],PrimeQ] (* Harvey P. Dale, Sep 06 2012 *)

Extensions

More terms from Harvey P. Dale, Sep 06 2012

A215994 Primes that are the sum of 151 consecutive primes.

Original entry on oeis.org

71011, 71941, 80429, 88079, 106699, 107699, 114761, 117809, 123863, 126949, 134287, 137437, 143719, 148961, 157457, 160627, 170063, 181871, 189467, 200467, 216023, 219377, 221603, 222713, 223829, 224951, 229433, 231661, 238373, 241727, 244009, 254383, 264731
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

Programs

  • Mathematica
    Select[Total/@Partition[Prime[Range[500]],151,1],PrimeQ] (* Harvey P. Dale, May 14 2017 *)

Extensions

More terms from Harvey P. Dale, May 14 2017

A215995 Primes that are the sum of 201 consecutive primes.

Original entry on oeis.org

115279, 130457, 131731, 135613, 162293, 163637, 164987, 173149, 179957, 201961, 204733, 214517, 230137, 231559, 232987, 244547, 257591, 259033, 267791, 273643, 283937, 292841, 313763, 319763, 322769, 325769, 336211, 342187, 349709, 352757, 371233, 372797
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

Programs

  • Mathematica
    Select[Total/@Partition[Prime[Range[2000]],201,1],PrimeQ] (* Harvey P. Dale, Nov 23 2016 *)

Extensions

More terms from Harvey P. Dale, Nov 23 2016

A215996 Primes that are the sum of 251 consecutive primes.

Original entry on oeis.org

198197, 199831, 204751, 208057, 216373, 218047, 219721, 224771, 229837, 247001, 248723, 250451, 262657, 269701, 330439, 352411, 363379, 367021, 385351, 387187, 389047, 415409, 421121, 434377, 440023, 441907, 449419, 453181, 458863, 468271, 483389, 487183
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

Programs

  • Mathematica
    Select[Total/@Partition[Prime[Range[600]],251,1],PrimeQ] (* Harvey P. Dale, Oct 18 2013 *)

Extensions

More terms from Harvey P. Dale, Oct 18 2013

A215997 Primes that are the sum of 301 consecutive primes.

Original entry on oeis.org

289099, 295201, 299287, 301331, 305419, 307471, 309523, 317771, 319831, 361961, 376921, 387623, 406969, 413461, 422209, 426583, 442019, 459817, 475369, 513067, 519769, 526501, 533257, 535511, 537773, 594821, 608759, 629689, 636697, 646013, 648341, 678883
Offset: 1

Views

Author

Syed Iddi Hasan, Aug 30 2012

Keywords

Crossrefs

Cf. A215991.

Extensions

More terms added from b-file by Andrew Howroyd, Feb 11 2018
Showing 1-10 of 32 results. Next