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 37 results. Next

A350827 Number of prime septuplets (i.e.: 7-tuples) with initial member (A022009 or A022010) between 10^(n-1) and 10^n.

Original entry on oeis.org

0, 1, 0, 1, 1, 4, 5, 21, 70, 370, 1862, 9634
Offset: 1

Views

Author

M. F. Hasler, Mar 01 2022

Keywords

Comments

"Between 10^(n-1) and 10^n" is equivalent to saying "with n digits".
Up to 10^600 at least, the largest term of all prime septuplets (= set of 7 consecutive primes {p1, ..., p7} with minimal possible diameter p7 - p1 = 20) has the same number of digits as the smallest term. (*)
Terms a(1)-a(12) computed from b-files a(1..10^4) for A022009 and A022010.
(*) We checked that n = 1, 2, 3, 5, 17 and 18 are the only values below 600 with more than 2 primes in the interval [10^n - 20, 10^n + 20]. So the probability of finding a 7-tuple with diameter 20 in such an interval seems exceedingly small. - M. F. Hasler, Apr 12 2022

Examples

			a(1) = a(3) = 0 because there is no single-digit nor a 3-digit prime to start a prime septuplet.
a(2) = a(4) = a(5) = 1 because 11 = A022009(1), 5639 = A022010(1) and 88799 = A022010(2) are the only prime with 2, 4 resp. 5 digits to start a prime septuplet.
Then there are a(6) = 4 six-digit primes, 165701, 284729, 626609 and 855719, which start a prime septuplet.
		

Crossrefs

Cf. A022009, A022010: initial members p of prime septuplets (p, p+2, p+6, ...) resp. (p, p+2, p+8, ...).
Cf. A350825, A350826, A350828: similar for quintuplets, sextuplets and octuplets.

Programs

  • PARI
    apply( {A350827(n,v=vector(6),c)=forprime(p=10^(n-1),10^n, v[n=1+n%#v]+20==(v[n]=p) && c++);c}, [1..8]) \\ becomes slow for n > 8. - M. F. Hasler, Apr 12 2022

A357889 a(n) = (A022010(n) - 179)/210.

Original entry on oeis.org

26, 422, 1355, 2983, 4074, 5460, 31242, 35906, 40825, 84968, 90902, 114293, 204675, 207304, 329316, 353648, 377182, 382985, 400497, 418993, 590790, 611757, 686734, 748244, 993947, 1038255, 1181931, 1246060, 1310026, 1347976, 1354707, 1440679, 1477788, 1559980, 1720425, 1915719, 1989590
Offset: 1

Views

Author

Hugo Pfoertner, Nov 18 2022

Keywords

Comments

Linear conversion of the initial members of prime septuplets of second type.
Numbers k such that 210*k+179, 210*k+181, 210*k+187, 210*k+191, 210*k+193, 210*k+197, and 210*k+199 are all primes. - Jianing Song, Nov 18 2022

Crossrefs

Cf. A022009, A022010, A182387 (similar for prime septuplets of first type).
A357890 is a subsequence.

A375645 Products of prime 7-tuples (p, p+2, p+8, p+12, p+14, p+18, p+20) where p = A022010(n).

Original entry on oeis.org

183698727318433150098859517, 43573095131179423946916455382173477, 151752127452301913425377267345374694407, 37933916719513692044984369353553394500687, 336012768546310957228958479424678156040797, 2608471791567290523882206574758483434858457, 523352977400310485591027030692542102863968347677
Offset: 1

Views

Author

Michael De Vlieger, Aug 23 2024

Keywords

Comments

Primes p in A022010 belong to 179 (mod 210), therefore a(n) is congruent to the product of residues {179, 181, 187, 191, 193, 197, 199} (mod 210), so a(n) is congruent to 17 (mod 210). Gaps between prime factors are {2, 6, 4, 2, 4, 2}.

Crossrefs

Programs

  • Mathematica
    Map[Times @@ NextPrime[#, Range[0, 6]] &, Select[Prime@ Range[2^20], AllTrue[# + {2, 8, 12, 14, 18, 20}, PrimeQ] &]]

A022009 Initial members of prime septuplets (p, p+2, p+6, p+8, p+12, p+18, p+20).

Original entry on oeis.org

11, 165701, 1068701, 11900501, 15760091, 18504371, 21036131, 25658441, 39431921, 45002591, 67816361, 86818211, 93625991, 124716071, 136261241, 140117051, 154635191, 162189101, 182403491, 186484211, 187029371, 190514321, 198453371
Offset: 1

Views

Author

Keywords

Comments

All terms are congruent to 11 (modulo 210). - Matt C. Anderson, May 26 2015
Also the terms k of A276848 for which k == 1 (mod 10), see the comment in A276848 and A276826. All terms are obviously also congruent to 11 (modulo 30). - Vladimir Shevelev, Sep 21 2016
See A343637 for the least prime septuplets > 10^n, n >= 0. - M. F. Hasler, Aug 04 2021

Crossrefs

Cf. A022010 (septuplets of the second type), A182387, A276826, A276848, A343637 (septuplet following 10^n).

Programs

  • Magma
    [p: p in PrimesUpTo(2*10^8) | forall{p+r: r in [2,6,8,12,18,20] | IsPrime(p+r)}]; // Vincenzo Librandi, Oct 01 2015
  • Mathematica
    Transpose[Select[Partition[Prime[Range[10400000]],7,1],Differences[#] == {2,4,2,4,6,2}&]][[1]] (* Harvey P. Dale, Jul 13 2014 *)
    Select[Prime[Range[2 10^8]], Union[PrimeQ[# + {2, 6, 8, 12, 18, 20}]] == {True} &] (* Vincenzo Librandi, Oct 01 2015 *)
  • PARI
    nextcomposite(n)=if(n<4, return(4)); n=ceil(n); if(isprime(n), n+1, n)
       is(n)=if(n%30!=11 || !isprime(n) || !isprime(n+2), return(0)); my(p=n, q=n+2, k=2, f); while(p!=q && q-p<7, f=if(isprime(k++), nextprime, nextcomposite); p=f(p+1); q=f(q+1)); p==q \\ Charles R Greathouse IV, Sep 30 2016
    
  • PARI
    select( {is_A022009(n)=n%210==11&&!foreach([20,18,12,8,6,2,0],d,isprime(n+d)||return)}, [11+k*210|k<-[0..10^5]]) \\ M. F. Hasler, Aug 04 2021
    
  • Perl
    use ntheory ":all"; say for sieve_prime_cluster(1,1e9, 2,6,8,12,18,20); # Dana Jacobsen, Sep 30 2015
    

Formula

a(n) = 210*A182387(n) + 11. - Hugo Pfoertner, Nov 18 2022

A257124 Initial members of prime septuplets.

Original entry on oeis.org

11, 5639, 88799, 165701, 284729, 626609, 855719, 1068701, 1146779, 6560999, 7540439, 8573429, 11900501, 15760091, 17843459, 18504371, 19089599, 21036131, 24001709, 25658441, 39431921, 42981929, 43534019, 45002591, 67816361, 69156539, 74266259, 79208399, 80427029, 84104549, 86818211, 87988709, 93625991, 124066079
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Apr 16 2015

Keywords

Crossrefs

Initial members of all of the first prime k-tuplets:
twin primes: A001359.
prime triples: A007529 out of A022004, A022005.
prime quadruplets: A007530.
prime 5-tuples: A086140 out of A022007, A022006.
prime sextuplets: A022008.
prime septuplets: this sequence out of A022009, A022010.
prime octuplets: A065706 out of A022011, A022012, A022013.
prime nonuplets: A257125 out of A022547, A022548, A022545, A022546.
prime decaplets: A257127 out of A027569, A027570.
prime 11-tuplets: A257129 out of A213646, A213647.
prime 12-tuplets: A257131 out of A213601, A213645.
prime 13-tuplets: A257135 out of A214947, A257137, A257138, A257139, A257140, A257141.
prime 14-tuplets: A257166 out of A257167, A257168.
prime 15-tuplets: A257169 out of A257304, A257305, A257306, A257307.
prime 16-tuplets: A257308 out of A257369, A257370.
prime 17-tuplets: A257373 out of A257374, A257375, A257376, A257377.
Cf. A343637 (distance from 10^n to the next septuplet).
Cf. A100418.

Formula

Disjoint union of A022009 and A022010. - M. F. Hasler, Aug 04 2021

A257125 Initial members of prime 9-tuplets (or nonuplets).

Original entry on oeis.org

7, 11, 13, 17, 1277, 88789, 113143, 113147, 855709, 74266249, 182403491, 226449521, 252277007, 408936947, 521481197, 626927443, 910935911, 964669609, 1042090781, 1116452627, 1209950867, 1422475909, 1459270271, 1645175087, 2117861719, 2335215973, 2558211559, 2843348351, 2873599429, 2966003057, 3447123283, 3947480417
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Apr 16 2015

Keywords

Comments

Primes prime(m) such that prime(m+8) = prime(m) + 30. - Zak Seidov, Jul 06 2015

Crossrefs

Initial members of all of the first prime k-tuplets:
twin primes: A001359.
prime triples: A007529 out of A022004, A022005.
prime quadruplets: A007530.
prime 5-tuples: A086140 out of A022007, A022006.
prime sextuplets: A022008.
prime septuplets: A257124 out of A022009, A022010.
prime octuplets: A065706 out of A022011, A022012, A022013.
prime nonuplets: this sequence out of A022547, A022548, A022545, A022546.
prime decaplets: A257127 out of A027569, A027570.
prime 11-tuplets: A257129 out of A213646, A213647.
prime 12-tuplets: A257131 out of A213601, A213645.
prime 13-tuplets: A257135 out of A214947, A257137, A257138, A257139, A257140, A257141.
prime 14-tuplets: A257166 out of A257167, A257168.
prime 15-tuplets: A257169 out of A257304, A257305, A257306, A257307.
prime 16-tuplets: A257308 out of A257369, A257370.
prime 17-tuplets: A257373 out of A257374, A257375, A257376, A257377.

Programs

  • Magma
    [NthPrime(n): n in [0..2*10^4] | NthPrime(n+8) eq (NthPrime(n) + 30)]; // Vincenzo Librandi, Jul 08 2015
  • Mathematica
    {p, q, r, s, t, u, v, w, x} = Prime@ Range@ 9; lst = {}; While[p < 1000000001, If[p + 30 == x, AppendTo[lst, p]; Print@ p]; {p, q, r, s, t, u, v, w, x} = {q, r, s, t, u, v, w, x, NextPrime@ x}]; lst (* Robert G. Wilson v, Jul 06 2015 *)
    Select[Partition[Prime[Range[5 10^6]],9,1],#[[1]]+30==#[[9]]&][[;;,1]] (* The program generates the first 10 terms of the sequence. To generate more, increase the Range constant. *) (* Harvey P. Dale, Jul 01 2024 *)
  • PARI
    main(size)=v=vector(size); i=0; m=1; while(iAnders Hellström, Jul 08 2015
    

A257127 Initial members of prime 10-tuplets (or decaplets).

Original entry on oeis.org

11, 9853497737, 21956291867, 22741837817, 33081664151, 83122625471, 164444511587, 179590045487, 217999764107, 231255798857, 242360943257, 294920291201, 573459229151, 663903555851, 666413245007, 688697679401, 696391309697, 730121110331, 867132039857, 974275568237, 976136848847, 1002263588297
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Apr 16 2015

Keywords

Crossrefs

Initial members of all of the first prime k-tuplets:
twin primes: A001359.
prime triples: A007529 out of A022004, A022005.
prime quadruplets: A007530.
prime quintuplets: A086140 out of A022007, A022006.
prime sextuplets: A022008.
prime septuplets: A257124 out of A022009, A022010.
prime octuplets: A065706 out of A022011, A022012, A022013.
prime nonuplets: A257125 out of A022547, A022548, A022545, A022546.
prime decaplets: this sequence out of A027569, A027570.
prime 11-tuplets: A257129 out of A213646, A213647.
prime 12-tuplets: A257131 out of A213601, A213645.
prime 13-tuplets: A257135 out of A214947, A257137, A257138, A257139, A257140, A257141.
prime 14-tuplets: A257166 out of A257167, A257168.
prime 15-tuplets: A257169 out of A257304, A257305, A257306, A257307.
prime 16-tuplets: A257308 out of A257369, A257370.
prime 17-tuplets: A257373 out of A257374, A257375, A257376, A257377.

A257129 Initial members of prime 11-tuples.

Original entry on oeis.org

11, 1418575498573, 2118274828903, 4396774576273, 6368171154193, 6953798916913, 7908189600581, 10527733922591, 12640876669691, 27899359258003, 28138953913303, 34460918582323, 38545620633251, 40362095929003, 42023308245613, 43564522846961, 44058461657443, 60268613366231, 60596839933361, 61062361183903, 71431649320301
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Apr 16 2015

Keywords

Comments

It appears that this lists only starting primes for one of the A083409(11) = 2 constellations with minimal diameter A008407(11) = 36, i.e., the union of A213646 and A213647, while there are other prime 11-tuples with larger diameter. - M. F. Hasler, Dec 03 2018

Crossrefs

Initial members of all of the first prime k-tuples:
twin primes: A001359.
prime triples: A007529 out of A022004, A022005.
prime quadruples: A007530.
prime quintuples: A086140 out of A022007, A022006.
prime sextuples: A022008.
prime septuples: A257124 out of A022009, A022010.
prime octuples: A065706 out of A022011, A022012, A022013.
prime nonuples: A257125 out of A022547, A022548, A022545, A022546.
prime 10-tuples: A257127 out of A027569, A027570.
prime 11-tuples: this sequence out of A213646, A213647.
prime 12-tuples: A257131 out of A213601, A213645.
prime 13-tuples: A257135 out of A214947, A257137, A257138, A257139, A257140, A257141.
prime 14-tuples: A257166 out of A257167, A257168.
prime 15-tuples: A257169 out of A257304, A257305, A257306, A257307.
prime 16-tuples: A257308 out of A257369, A257370.
prime 17-tuples: A257373 out of A257374, A257375, A257376, A257377.

A257131 Initial members of prime 12-tuplets.

Original entry on oeis.org

11, 1418575498567, 27899359257997, 34460918582317, 76075560855367, 186460616596327, 218021188549237, 234280497145537, 282854319391717, 345120905374087, 346117552180627, 380284918609481, 437163765888581, 604439135284057, 701889794782061, 727417501795057, 980125031081081, 1041814617748747, 1090754719898917, 1277156391416021, 1487854607298791
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Apr 16 2015

Keywords

Crossrefs

Initial members of all of the first prime k-tuplets:
twin primes: A001359.
prime triples: A007529 out of A022004, A022005.
prime quadruplets: A007530.
prime 5-tuples: A086140 out of A022007, A022006.
prime sextuplets: A022008.
prime septuplets: A257124 out of A022009, A022010.
prime octuplets: A065706 out of A022011, A022012, A022013.
prime nonuplets: A257125 out of A022547, A022548, A022545, A022546.
prime decaplets: A257127 out of A027569, A027570.
prime 11-tuplets: A257129 out of A213646, A213647.
prime 12-tuplets: this sequence out of A213601, A213645.
prime 13-tuplets: A257135 out of A214947, A257137, A257138, A257139, A257140, A257141.
prime 14-tuplets: A257166 out of A257167, A257168.
prime 15-tuplets: A257169 out of A257304, A257305, A257306, A257307.
prime 16-tuplets: A257308 out of A257369, A257370.
prime 17-tuplets: A257373 out of A257374, A257375, A257376, A257377.

A257135 Initial members of prime 13-tuplets.

Original entry on oeis.org

11, 13, 10527733922579, 186460616596321, 1707898733581273, 3266590043460823, 4289907938811613, 4422879865247923, 5693002600430263, 7582919852522851, 7697168877290909, 7933248530182091, 10071192314217869, 10907318641689703, 11987120084474369, 15991086371740199, 20475715985020181, 21817283854511261, 21817283854511263, 22443709342850669, 28561589689237439, 31979851757518501
Offset: 1

Views

Author

Tim Johannes Ohrtmann, Apr 16 2015

Keywords

Crossrefs

Initial members of all of the first prime k-tuplets:
twin primes: A001359.
prime triples: A007529 out of A022004, A022005.
prime quadruplets: A007530.
prime 5-tuples: A086140 out of A022007, A022006.
prime sextuplets: A022008.
prime septuplets: A257124 out of A022009, A022010.
prime octuplets: A065706 out of A022011, A022012, A022013.
prime nonuplets: A257125 out of A022547, A022548, A022545, A022546.
prime decaplets: A257127 out of A027569, A027570.
prime 11-tuplets: A257129 out of A213646, A213647.
prime 12-tuplets: A257131 out of A213601, A213645.
prime 13-tuplets: this sequence out of A214947, A257137, A257138, A257139, A257140, A257141.
prime 14-tuplets: A257166 out of A257167, A257168.
prime 15-tuplets: A257169 out of A257304, A257305, A257306, A257307.
prime 16-tuplets: A257308 out of A257369, A257370.
prime 17-tuplets: A257373 out of A257374, A257375, A257376, A257377.
Showing 1-10 of 37 results. Next