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.

Previous Showing 11-16 of 16 results.

A096704 Balanced primes of order twelve.

Original entry on oeis.org

157, 173, 709, 827, 1999, 2689, 6803, 11351, 11489, 12757, 15277, 33071, 37967, 38449, 46751, 47303, 51599, 53113, 56779, 57269, 59107, 62731, 62743, 62791, 63649, 77023, 79357, 81553, 81649, 81953, 85621, 96377, 108139, 113983, 117839
Offset: 1

Views

Author

Robert G. Wilson v, Jun 26 2004

Keywords

Examples

			157 is a term because 157 = (97 + 101 + 103 + 107 + 109 + 113 + 127 + 131 + 137 + 139 + 149 + 151 + 157 + 163 + 167 + 173 + 179 + 181 + 191 + 193 + 197 + 199 + 211 + 223 + 227)/25 = 3925/25.
		

Crossrefs

Programs

  • GAP
    P:=Filtered([1..150000],IsPrime);;
    a:=List(Filtered(List([0..12000],k->List([1..25],j->P[j+k])),i->Sum(i)/25=i[13]),m->m[13]); # Muniru A Asiru, Mar 04 2018
  • Mathematica
    Select[Partition[Prime[Range[12000]],25,1],Mean[#]==#[[13]]&][[All,13]] (* Harvey P. Dale, Jun 28 2020 *)

A090403 Balanced primes: Primes which are both the arithmetic mean and median of a sequence of 2k+1 consecutive primes, for some k>0.

Original entry on oeis.org

5, 17, 29, 37, 53, 71, 79, 89, 137, 149, 151, 157, 173, 179, 193, 211, 227, 229, 257, 263, 281, 349, 353, 359, 373, 383, 397, 409, 419, 421, 433, 439, 487, 491, 563, 577, 593, 607, 631, 643, 653, 659, 677, 701, 709, 733, 751, 757, 787, 823, 827, 877, 947, 953
Offset: 1

Views

Author

Farideh Firoozbakht, Dec 07 2003

Keywords

Comments

Union, for all k>0, of (2k+1)-balanced prime numbers, i.e., balanced prime of order k, which are primes p_n such that (2k+1)*p_n = Sum_{i=n-k..n+k} p_i, where p_i is the i-th prime.

Examples

			17 is in the sequence because 17 = (7 + 11 + 13 + 17 + 19 + 23 + 29)/7, (k = 3).
29 is in the sequence because 29 = (5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59)/15, (k = 7).
37 is a member because 37 = (7 + 11 + 13 + 17 + 19 + 23 + 29 + 31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71)/17; 7 & 71 are eight primes away from 37.
		

Crossrefs

Programs

  • Mathematica
    t[n_] := (For[k=1, !(SameQ[1/(2k+1)Sum[Prime[i], {i, n-k, n+k}], Prime[n]])&& k < n-1, k++ ];k);b[n_] := If[t[n]
    				
  • PARI
    is_A090403(p)={my(s=0,n); isprime(p) & for(k=1,-1+n=primepi(p),(s+=prime(n+k)+prime(n-k)-2*p)||return(1);s>p & return)} \\ M. F. Hasler, Oct 21 2012

Extensions

Definition corrected by Franklin T. Adams-Watters, Apr 13 2006
Edited by M. F. Hasler, Oct 21 2012

A082080 Smallest balanced prime of order n.

Original entry on oeis.org

2, 5, 79, 17, 491, 53, 71, 29, 37, 983, 5503, 173, 157, 353, 5297, 263, 179, 383, 137, 2939, 2083, 751, 353, 5501, 1523, 149, 4561, 1259, 397, 787, 8803, 8803, 607, 227, 3671, 17443, 57097, 3607, 23671, 12539, 1217, 11087, 1087, 21407, 19759, 953
Offset: 0

Views

Author

Labos Elemer, Apr 08 2003

Keywords

Comments

Or, smallest (2n+1)-balanced prime number.
Prime(k) is a balanced prime of order n if it is the average of the 2n+1 primes from prime(k-n) to prime(k+n).

Examples

			a(1) = 5 = (3 + 5 + 7)/3 = 15/3.
a(5) = 53 = (31 + 37 + 41 + 43 + 47 + 53 + 59 + 61 + 67 + 71 + 73)/11 = 583/11.
a(6) = 71 = (43 + 47 + 53 + 59 + 61 + 67 + 71 + 73 + 79 + 83 + 89 + 97 + 101)/13 = 923/13.
		

Crossrefs

Programs

  • Mathematica
    f[n_] := Block[{p = Prime@ Range[2n +1]}, While[ Total[p] != (2n +1) p[[n +1]], p = Join[Rest@ p, {NextPrime[ p[[-1]]] }]]; p[[n +1]]]; Array[f, 46, 0] (* Robert G. Wilson v, Jun 21 2004 and modified Apr 11 2017 *)
  • PARI
    for(n=0, 50, i=2*n+1;f=0;forprime(p=2, 10^7, s=0;c=i;pr=p-1;t=0;while(c>0, c=c-1;pr=nextprime(pr+1);s=s+pr; if(c==(i-1)/2, t=pr)); if(s/i==t, print1(t", ");f=1;break)); if(!f, print1("0, ")))

Extensions

Corrected and extended by Ralf Stephan, Apr 09 2003

A300365 Balanced primes of order fourteen.

Original entry on oeis.org

5297, 15647, 22073, 22501, 26309, 34721, 43499, 44111, 48809, 57529, 58171, 66797, 69151, 70199, 74551, 76493, 86959, 91297, 93169, 93199, 94343, 102217, 110777, 112289, 113093, 132361, 133493, 135461, 139921, 146021, 155303, 156521, 162557, 163753, 163789
Offset: 1

Views

Author

Muniru A Asiru, Mar 04 2018

Keywords

Examples

			5297 is a member because 5297 = 5167 + 5171 + 5179 + 5189 + 5197 + 5209 + 5227 + 5231 + 5233 + 5237 + 5261 + 5273 + 5279 + 5281 + 5297 + 5303 + 5309 + 5323 + 5333 + 5347 + 5351 + 5381 + 5387 + 5393 + 5399 + 5407 + 5413 + 5417 + 5419  = 153613/29.
		

Crossrefs

Cf. Balanced primes of order b: A006562 (b=1), A082077 (b=2), A082078 (b=3), A082079 (b=4), A096697 (b=5), A096698 (b=6), A096699 (b=7), A096700 (b=8), A096701 (b=9), A096702 (b=10), A096703 (b=11), A096704 (b=12), A300364 (b=13) this sequence (b=14).

Programs

  • GAP
    P:=Filtered([1..200000],IsPrime);;
    a:=List(Filtered(List([0..17000],k->List([1..29],j->P[j+k])),i->Sum(i)/29=i[15]),m->m[15]);
  • Mathematica
    Module[{bal=14,nn=16000},Select[Partition[Prime[Range[nn]],2bal+1,1],Mean[#]==#[[bal+1]]&]][[;;,15]] (* Harvey P. Dale, Jul 07 2023 *)

A300364 Balanced primes of order thirteen.

Original entry on oeis.org

353, 2351, 3673, 3863, 4759, 6271, 8539, 8821, 11261, 12073, 17839, 26711, 32797, 33769, 34679, 41357, 53269, 60217, 64879, 64891, 68713, 88493, 90121, 91811, 101347, 101411, 101641, 108139, 108203, 114659, 122029, 123637, 127843, 128237, 130447, 133279
Offset: 1

Views

Author

Muniru A Asiru, Mar 04 2018

Keywords

Examples

			353 is a member because 353 = 271 + 277 + 281 + 283 + 293 + 307 + 311 + 313 + 317 + 331 + 337 + 347 + 349 + 353 + 359 + 367 + 373 + 379 + 383 + 389 + 397 + 401 + 409 + 419 + 421 + 431 + 433 = 9531/27.
		

Crossrefs

Cf. Balanced primes of order b: A006562 (b=1), A082077 (b=2), A082078 (b=3), A082079 (b=4), A096697 (b=5), A096698 (b=6), A096699 (b=7), A096700 (b=8), A096701 (b=9), A096702 (b=10), A096703 (b=11), A096704 (b=12), this sequence (b=13), A300365 (b=14).

Programs

  • GAP
    P:=Filtered([1..150000],IsPrime);;
    a:=List(Filtered(List([0..13000],k->List([1..27],j->P[j+k])),i->Sum(i)/27=i[14]),m->m[14]);

A363168 Balanced primes of order 100.

Original entry on oeis.org

27947, 111337, 193283, 197341, 197621, 347063, 809821, 955193, 1029803, 1184269, 1292971, 1609163, 1630859, 1656019, 1752449, 1883381, 1935517, 1969661, 2120221, 2156383, 2238959, 2287133, 2548631, 2592089, 2750903, 2866403, 3165769, 3257941, 3590299, 3889423
Offset: 1

Views

Author

Harvey P. Dale, Jul 07 2023

Keywords

Comments

A prime p is in this sequence if the sum of the 100 consecutive primes just less than p, plus p, plus the sum of the 100 consecutive primes just greater than p, divided by 201 equals p.

Crossrefs

Cf. Balanced primes of order b: A006562 (b=1), A082077 (b=2), A082078 (b=3), A082079 (b=4), A096697 (b=5), A096698 (b=6), A096699 (b=7), A096700 (b=8), A096701 (b=9), A096702 (b=10), A096703 (b=11), A096704 (b=12), A300364 (b=13), A300365 (b=14).

Programs

  • Mathematica
    Module[{bal=100,nn=300000},Select[Partition[Prime[Range[nn]],2bal+1,1],Mean[#]== #[[bal+1]]&]] [[;;,101]]
Previous Showing 11-16 of 16 results.