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.

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A054832 Fifth term of weak prime sextet: p(m-3)-p(m-4) < p(m-2)-p(m-3) < p(m-1)-p(m-2) < p(m)-p(m-1) < p(m+1)-p(m).

Original entry on oeis.org

2939, 13499, 13921, 14983, 15401, 15413, 21433, 21577, 21893, 28297, 30911, 33247, 35617, 37747, 42257, 42611, 45841, 55681, 64693, 64951, 64969, 68227, 68239, 68917, 68927, 73973, 74231, 78623, 83137, 85549, 87359, 88037, 90947
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Crossrefs

Programs

  • Mathematica
    Select[Partition[Prime[Range[8800]],6,1],Min[Differences[#,2]]>0&][[All,5]] (* Harvey P. Dale, Feb 22 2020 *)

A054836 Third term of weak prime septet: p(m-1)-p(m-2) < p(m)-p(m-1) < p(m+1)-p(m) < p(m+2)-p(m+1) < p(m+3)-p(m+2) < p(m+4)-p(m+3).

Original entry on oeis.org

15383, 64927, 68213, 68903, 128987, 128993, 143519, 154087, 158009, 192383, 221723, 222403, 244471, 249737, 285301, 318683, 337283, 354377, 357839, 374189, 385397, 394733, 402587, 402593, 419603, 439171, 441923, 448387, 457403, 457679, 458197, 482513, 527987, 529819, 577537, 582767
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Crossrefs

Cf. A051635; A054800 .. A054803: members of balanced prime quartets (= 4 consecutive primes in arithmetic progression); A054804 .. A054818: members of strong prime quartet, quintet, sextet; A054819 .. A054840: members of weak prime quartet, quintet, sextet, septets.

Formula

a(n) = A151800(A054835(n)) = A151799(A054838(n)), A151800 = nextprime, A151799 = prevprime; A054836 = { m = A054829(n) | m = nextprime(A054829(n-1)) }. - M. F. Hasler, Oct 27 2018

Extensions

More terms from M. F. Hasler, Oct 27 2018

A054839 Sixth term of weak prime septet: p(m-4)-p(m-5) < p(m-3)-p(m-4) < p(m-2)-p(m-3) < p(m-1)-p(m-2) < p(m)-p(m-1) < p(m+1)-p(m).

Original entry on oeis.org

15413, 64969, 68239, 68927, 129011, 129023, 143551, 154127, 158047, 192431, 221747, 222461, 244507, 249779, 285377, 318713, 337313, 354401, 357913, 374239, 385433, 394759, 402613, 402631, 419651, 439217, 441971, 448451, 457433, 457711, 458239, 482539, 528013
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Crossrefs

Cf. A051635; A054800 .. A054803: members of balanced prime quartets (= consecutive primes in arithmetic progression); A054804 .. A054818: members of strong prime quartets, quintets, sextets; A054819 .. A054840: members of weak prime quartets, quintets, sextets, septets.

Programs

  • Mathematica
    Transpose[Select[Partition[Prime[Range[50000]],7,1],Min[ Differences[ #,2]]> 0&]][[6]] (* Harvey P. Dale, Sep 27 2015 *)

Formula

a(n) = A151800(A054838(n)) = A151799(A054840(n)), A054839 = { m = A054832(n) | m = A151800(A054832(n-1)) } (A151800: nextprime, A151799: prevprime). - M. F. Hasler, Oct 27 2018

Extensions

More terms from Harvey P. Dale, Sep 27 2015

A102552 a(n) = prime(n) - (prime(n+1) + prime(n-1))/2.

Original entry on oeis.org

0, -1, 1, -1, 1, -1, -1, 2, -2, 1, 1, -1, -1, 0, 2, -2, 1, 1, -2, 1, -1, -1, 2, 1, -1, 1, -1, -5, 5, -1, 2, -4, 4, -2, 0, 1, -1, 0, 2, -4, 4, -1, 1, -5, 0, 4, 1, -1, -1, 2, -4, 2, 0, 0, 2, -2, 1, 1, -4, -2, 5, 1, -1, -5, 4, -2, 4, -1, -1, -1, 1, 0, 1, -1, -1, 2, -2, -1, 4, -4, 4, -2, 1, -1, -1, 2, 1, -1, -4, 2, 2, -2, 2, -1, -3, 5, -8, 6, -2, 2, 0, 2, -2
Offset: 3

Views

Author

Yasutoshi Kohmoto, Feb 25 2005

Keywords

Examples

			a(6)=-1 because 13-(17+11)/2=-1.
		

References

  • Eric Weisstein, CRC Concise Encyclopedia of Mathematics, 1998, page 1321.

Crossrefs

Programs

  • Magma
    A102552:= func< n | (2*NthPrime(n)-NthPrime(n+1)-NthPrime(n-1))/2 >;
    [A102552(n): n in [3..120]]; // G. C. Greubel, Feb 02 2025
  • Maple
    a:=n->ithprime(n)-(ithprime(n+1)+ithprime(n-1))/2: seq(a(n),n=3..95); # Emeric Deutsch, Mar 02 2005
  • Mathematica
    f[n_] := Prime[n] - (Prime[n - 1] + Prime[n + 1])/2; Table[f[n], {n, 3, 107}] (* Robert G. Wilson v, Sep 25 2006 *)
    #[[2]]-(#[[1]]+#[[3]])/2&/@Partition[Prime[Range[2,110]],3,1] (* Harvey P. Dale, Sep 21 2013 *)
  • PARI
    a(n) = prime(n)-(prime(n+1)+prime(n-1))/2;
    vector(100,n,a(n+2)) \\ Joerg Arndt, Jan 20 2015
    
  • Python
    from sympy import sieve as p
    def A102552(n): return p[n]-(p[n+1]+p[n-1])//2 # Karl-Heinz Hofmann, May 22 2024
    

Formula

a(n) = (1/2)*(A001223(n) - A001223(n+1)).
a(n) = -A036263(n-1)/2. - T. D. Noe, Oct 06 2006 [corrected by Georg Fischer, Oct 19 2023]

Extensions

More terms from Emeric Deutsch, Mar 02 2005

A175102 1, followed by list of numbers n such that the number of strong primes and the number of weak primes are equal at the n-th prime.

Original entry on oeis.org

1, 60, 64, 41192, 41194, 41247, 41250, 41252, 41257, 41259, 41261, 41263, 41265, 41267, 41273, 41275, 41277, 41279, 41287, 41317, 41319, 41321, 41323, 41325, 41327, 41328, 41329, 41335, 41336, 41338, 41339, 41341, 41389, 41393, 41397, 41399, 41401, 41404, 41406, 41408, 41412, 41444, 41448, 42112
Offset: 1

Views

Author

G. L. Honaker, Jr., Dec 02 2010

Keywords

Comments

Also, indices of zeros in A092243. - N. J. A. Sloane, Mar 13 2016

Crossrefs

Programs

  • PARI
    my(c=1, q=3, r=2, s=0); print1(c, ", "); forprime(p=5, default(primelimit), c++;(s+=sign(r+0-2*(r=q)+q=p))||print1(c, ", ")) \\ M. F. Hasler, Dec 03 2010

Extensions

More terms from Chris K. Caldwell

A054811 Fourth term of strong prime quintets: p(m-2)-p(m-3) > p(m-1)-p(m-2) > p(m)-p(m-1) > p(m+1)-p(m).

Original entry on oeis.org

1667, 1787, 1867, 1871, 1997, 2381, 2473, 2531, 2539, 3457, 3461, 4217, 4517, 5279, 5417, 5441, 6043, 6659, 7243, 7307, 7757, 7877, 7933, 8167, 8521, 9613, 9619, 11057, 11393, 11593, 11831, 12409, 13877, 14827, 15137, 15551, 16061, 16333
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Comments

First member of pairs of consecutive primes in A054807 (4th of strong prime quartets). - M. F. Hasler, Oct 27 2018

Crossrefs

Cf. A051634, A051635; A054800 .. A054803: members of balanced prime quartets (= 4 consecutive primes in arithmetic progression); A054804 .. A054818: members of strong prime quartets, quintets, sextets; A054819 .. A054840: members of weak prime quartets, quintets, sextets, septets.

Formula

a(n) = nextprime(A054810(n)) = prevprime(A054812(n)), nextprime = A151800, prevprime = A151799; A054811 = {m = A054807(n) | nextprime(m) = A054807(n+1)}. - M. F. Hasler, Oct 27 2018

A054812 Fifth term of strong prime quintets: p(m-3)-p(m-4) > p(m-2)-p(m-3) > p(m-1)-p(m-2) > p(m)-p(m-1).

Original entry on oeis.org

1669, 1789, 1871, 1873, 1999, 2383, 2477, 2539, 2543, 3461, 3463, 4219, 4519, 5281, 5419, 5443, 6047, 6661, 7247, 7309, 7759, 7879, 7937, 8171, 8527, 9619, 9623, 11059, 11399, 11597, 11833, 12413, 13879, 14831, 15139, 15559, 16063, 16339
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Comments

Second member of pairs of consecutive primes in A054807 (4th term of strong prime quartets). - M. F. Hasler, Oct 27 2018

Crossrefs

Cf. A051634, A051635; A054800 .. A054803: members of balanced prime quartets (= 4 consecutive primes in arithmetic progression); A054804 .. A054818: members of strong prime quartets, quintets, sextets; A054819 .. A054840: members of weak prime quartets, quintets, sextets, septets.

Programs

  • Mathematica
    spqQ[c_]:=Module[{d=Differences[c]},d[[1]]>d[[2]]>d[[3]]>d[[4]]]; Transpose[ Select[Partition[Prime[Range[2000]],5,1],spqQ]][[5]] (* Harvey P. Dale, Jan 01 2013 *)

Formula

a(n) = nextprime(A054811(n)); A054811 = {m = A054807(n) | prevprime(m) = A054807(n-1)}; nextprime = A151800, prevprime = A151799. - M. F. Hasler, Oct 27 2018

A054813 First term of strong prime sextets: p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2) > p(m+4)-p(m+3) > p(m+5)-p(m+4).

Original entry on oeis.org

1831, 2477, 3413, 9551, 21433, 22973, 25189, 26053, 32143, 33359, 33893, 39047, 40771, 41203, 44221, 47251, 48787, 55849, 57751, 66977, 70079, 74231, 74653, 74687, 75083, 75109, 82913, 84263, 87811, 88339, 88609, 103723, 103843, 106219, 106921, 108139, 110881, 112979, 118093
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Crossrefs

Cf. A051634, A051635; A054800 .. A054803: members of balanced prime quartets (= consecutive primes in arithmetic progression); A054804 .. A054818: members of strong prime quartet, quintet, sextet; A054819 .. A054840: members of weak prime quartet, quintet, sextet, septets.

Formula

a(n) = A151799(A054814(n)), A054813 = { m = A054808(n) | m = A151799(A054808(n+1)) }, where A151799 = next smaller prime. - M. F. Hasler, Oct 27 2018

Extensions

More terms and offset corrected to 1 by M. F. Hasler, Oct 27 2018

A054814 Second term p(m) of strong prime sextets: p(m)-p(m-1) > p(m+1)-p(m) > p(m+2)-p(m+1) > p(m+3)-p(m+2) > p(m+4)-p(m+3).

Original entry on oeis.org

1847, 2503, 3433, 9587, 21467, 22993, 25219, 26083, 32159, 33377, 33911, 39079, 40787, 41213, 44249, 47269, 48799, 55871, 57773, 67003, 70099, 74257, 74687, 74699, 75109, 75133, 82939, 84299, 87833, 88379, 88643, 103769, 103867, 106243, 106937, 108161, 110899, 112997, 118127, 120371
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Crossrefs

Cf. A051634, A051635; A054800 .. A054803: members of balanced prime quartets (= consecutive primes in arithmetic progression); A054804 .. A054818: members of strong prime quartet, quintet, sextet; A054819 .. A054840: members of weak prime quartet, quintet, sextet, septets.
Subsequence of A054808.

Programs

  • Mathematica
    Select[Partition[Prime[Range[12000]],6,1],Max[Differences[#,2]]<0&][[;;,2]] (* Harvey P. Dale, Jun 17 2023 *)

Formula

a(n) = A151800(A054813(n)) = A151799(A054815(n)), A151800 = nextprime, A151799 = prevprime; A054814 = { m = A054809(n) | m = nextprime(A054809(n-1)) }. - M. F. Hasler, Oct 27 2018

Extensions

Edited and offset changed to 1 by M. F. Hasler, Oct 26 2018

A054824 Second term of weak prime quintets: p(m)-p(m-1) < p(m+1)-p(m) < p(m+2)-p(m+1) < p(m+3)-p(m+2).

Original entry on oeis.org

349, 677, 1429, 1489, 1621, 2207, 2239, 2689, 2909, 2917, 4093, 4129, 4933, 5573, 5927, 6271, 6473, 6703, 6829, 8089, 8171, 8233, 8933, 10333, 10733, 11779, 12109, 12281, 13469, 13477, 13903, 13907, 14083, 14629, 14657, 14951, 14957, 15077
Offset: 1

Views

Author

Henry Bottomley, Apr 10 2000

Keywords

Comments

a(1) = A229832(3). - Jonathan Sondow, Oct 13 2013

Crossrefs

Programs

  • Mathematica
    wpqQ[{a_,b_,c_,d_,e_}]:=b-aHarvey P. Dale, Jul 29 2019 *)
Previous Showing 21-30 of 49 results. Next