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 1-3 of 3 results.

A022532 Nexus numbers (n+1)^16-n^16.

Original entry on oeis.org

1, 65535, 42981185, 4251920575, 148292923329, 2668522016831, 30411820662145, 248242046141055, 1571545212141185, 8146979811148159, 35949729863572161, 138934529031464255, 480532350288143425, 1512536728626191295, 4390455017903519489, 11878335717996660991
Offset: 0

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Author

Keywords

References

  • J. H. Conway and R. K. Guy, The Book of Numbers, Copernicus Press, NY, 1996, p. 54.

Crossrefs

Column k=15 of A047969.
Cf. A010804 (n^16).

Programs

  • Magma
    [(n+1)^16-n^16: n in [0..20]]; // Vincenzo Librandi, Nov 22 2011
    
  • Maple
    b:=16: a:=n->(n+1)^b-n^b: seq(a(n),n=0..18); # Muniru A Asiru, Feb 28 2018
  • Mathematica
    Table[(n+1)^16-n^16,{n,0,20}] (* Vincenzo Librandi, Nov 22 2011 *)
  • PARI
    for(n=0,20, print1((n+1)^16 - n^16, ", ")) \\ G. C. Greubel, Feb 27 2018

Formula

a(n) = A010804(n+1) - A010804(n). - Michel Marcus, Feb 28 2018

Extensions

More terms added by G. C. Greubel, Feb 27 2018

A170780 a(n) = n^8*(n^8 + 1)/2.

Original entry on oeis.org

0, 1, 32896, 21526641, 2147516416, 76294140625, 1410555793536, 16616468167201, 140737496743936, 926510115949281, 5000000050000000, 22974865038965521, 92442129662509056, 332708304999455281, 1088976669642580096
Offset: 0

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Author

N. J. A. Sloane, Dec 11 2009

Keywords

Comments

Number of unoriented rows of length 16 using up to n colors. For a(0)=0, there are no rows using no colors. For a(1)=1, there is one row using that one color for all positions. For a(2)=32896, there are 2^16=65536 oriented arrangements of two colors. Of these, 2^8=256 are achiral. That leaves (65536-256)/2=32640 chiral pairs. Adding achiral and chiral, we get 32896. - Robert A. Russell, Nov 13 2018

Crossrefs

Row 16 of A277504.
Cf. A010804 (oriented), A001016 (achiral).

Programs

  • GAP
    List([0..30], n -> n^8*(n^8+1)/2); # G. C. Greubel, Nov 15 2018
    
  • Magma
    [n^8*(n^8+1)/2: n in [0..30]]; // Vincenzo Librandi, Aug 26 2011
    
  • Mathematica
    Table[n^8*(n^8+1)/2, {n, 0, 30}] (* G. C. Greubel, Dec 05 2017 *)
  • PARI
    for(n=0, 30, print1(n^8*(n^8+1)/2, ", ")) \\ G. C. Greubel, Dec 05 2017
    
  • Python
    for n in range(0,20): print(int(n**8*(n**8 + 1)/2), end=', ') # Stefano Spezia, Nov 15 2018
  • Sage
    [n^8*(n^8+1)/2 for n in range(30)] # G. C. Greubel, Nov 15 2018
    

Formula

G.f.: (x + 32879*x^2 + 20967545*x^3 + 1786036695*x^4 + 42691617829* x^5 + 391057805899*x^6 + 1603741496717*x^7 + 3191399514435*x^8 + 3191399514435*x^9 + 1603741496717*x^10 + 391057805899*x^11 + 42691617829*x^12 + 1786036695*x^13 + 20967545*x^14 + 32879*x^15 + x^16) /(1-x)^17. - G. C. Greubel, Dec 05 2017
From Robert A. Russell, Nov 13 2018: (Start)
a(n) = (A010804(n) + A001016(n)) / 2 = (n^16 + n^8) / 2.
G.f.: (Sum_{j=1..16} S2(16,j)*j!*x^j/(1-x)^(j+1) + Sum_{j=1..8} S2(8,j)*j!*x^j/(1-x)^(j+1)) / 2, where S2 is the Stirling subset number A008277.
G.f.: x*Sum_{k=0..15} A145882(16,k) * x^k / (1-x)^17.
E.g.f.: (Sum_{k=1..16} S2(16,k)*x^k + Sum_{k=1..8} S2(8,k)*x^k) * exp(x) / 2, where S2 is the Stirling subset number A008277.
For n>16, a(n) = Sum_{j=1..17} -binomial(j-18,j) * a(n-j). (End)

A309012 Number of ordered pairs (i,j) with 0 < i < j < prime(n)/2 such that (i^16 mod prime(n)) > (j^16 mod prime(n)).

Original entry on oeis.org

0, 0, 0, 0, 3, 3, 0, 16, 21, 43, 30, 62, 77, 99, 129, 146, 203, 187, 228, 245, 252, 345, 372, 382, 402, 558, 570, 631, 663, 756, 901, 1114, 961, 1325, 1398, 1253, 1571, 1470, 1601, 1795, 2024, 1988, 2349, 2014, 2184, 2200, 2728, 3054, 3084, 3718, 3386, 3224, 3018, 3861, 3866, 4258, 4361, 4418, 5110, 4724
Offset: 1

Views

Author

Zhi-Wei Sun, Jul 06 2019

Keywords

Comments

Conjecture : Let p be an odd prime, and let N be the number of ordered pairs (i,j) with 0 < i < j < p/2 and (i^16 mod p) > (j^16 mod p). When p == 1 (mod 16), we have 2 | N. Also, N == |{0

Examples

			a(5) = 3 with prime(5) = 11, and (2^16 mod 11) = 9 greater than (3^16 mod 11) = 3, (4^16 mod 11) = 4 and (5^16 mod 11) = 5.
		

Programs

  • Mathematica
    r[p_]:=r[p]=Sum[Boole[PowerMod[j,16,p]>PowerMod[k,16,p]],{k,2,p/2},{j,1,k-1}];
    Print[Table[r[Prime[n]],{n,1,60}]]
Showing 1-3 of 3 results.