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 1-4 of 4 results.

A255499 a(n) = (n^4 + 2*n^3 - n^2)/2.

Original entry on oeis.org

0, 1, 14, 63, 184, 425, 846, 1519, 2528, 3969, 5950, 8591, 12024, 16393, 21854, 28575, 36736, 46529, 58158, 71839, 87800, 106281, 127534, 151823, 179424, 210625, 245726, 285039, 328888, 377609, 431550, 491071, 556544, 628353, 706894, 792575, 885816, 987049, 1096718, 1215279, 1343200
Offset: 0

Views

Author

N. J. A. Sloane, Mar 13 2015

Keywords

Crossrefs

Cf. A229738.

Programs

  • Magma
    [n^4/2+n^3-n^2/2: n in [0..40]] // Vincenzo Librandi, Sep 05 2015
    
  • Mathematica
    Table[n^4/2 + n^3 - n^2/2, {n, 0, 60}] (* or *) CoefficientList[Series[x (1 + 9 x + 3 x^2 - x^3)/(1 - x)^5, {x, 0, 45}], x] (* Vincenzo Librandi, Sep 05 2015 *)
    LinearRecurrence[{5,-10,10,-5,1},{0,1,14,63,184},50] (* Harvey P. Dale, Nov 11 2017 *)
  • PARI
    a(n) = n^4/2+n^3-n^2/2; \\ Michel Marcus, Sep 05 2015
    
  • Sage
    [n^2*(n^2 +2*n -1)/2 for n in (0..40)] # G. C. Greubel, Sep 24 2021

Formula

G.f.: x*(1+9*x+3*x^2-x^3)/(1-x)^5. - Vincenzo Librandi, Sep 05 2015
a(n) = 5*a(n-1) -10*a(n-2) +10*a(n-3) -5*a(n-4) +a(n-5). - Vincenzo Librandi, Sep 05 2015
a(n) = Sum_{k=n..n+n^2-1} k (the sum of the first n^2 integers starting with n). - Matthew Niemiro, Jun 26 2020
E.g.f.: (x/2)*(2 +12*x +8*x^2 +x^3)*exp(x). - G. C. Greubel, Sep 24 2021

A255500 a(n) = (p^9 + 5*p^8 + 4*p^7 - p^6 - 5*p^5 + 2*p^4)/6 where p is the n-th prime.

Original entry on oeis.org

352, 9909, 698125, 12045817, 584190541, 2487920149, 25846158097, 68520305701, 367691205289, 2846113596901, 5135516500321, 24650159312557, 61346708983561, 93685639700269, 206700247118737, 602622774810109, 1567842813615901, 2110866318916741, 4876836410298997
Offset: 1

Views

Author

N. J. A. Sloane, Mar 13 2015

Keywords

Crossrefs

Programs

  • Mathematica
    Table[(p^9+5p^8+4p^7-p^6-5p^5+2p^4)/6,{p,Prime[Range[20]]}] (* Harvey P. Dale, May 23 2020 *)
  • Python
    from _future_ import division
    from sympy import prime
    A255500_list = []
    for n in range(1,10**2):
        p = prime(n)
        A255500_list.append(p**4*(p*(p*(p*(p*(p + 5) + 4) - 1) - 5) + 2)//6)
    # Chai Wah Wu, Mar 14 2015
    
  • Sage
    def p(n): return nth_prime(n)
    def A255500(n): return p(n)^4*(p(n)^5 +5*p(n)^4 +4*p(n)^3 -p(n)^2 -5*p(n) +2)/6
    [A255500(n) for n in (1..30)] # G. C. Greubel, Sep 24 2021

A229739 a(n) = q^2*(q^2+2*q-1)/2, where q = n-th prime power A000961(n).

Original entry on oeis.org

1, 14, 63, 184, 425, 1519, 2528, 3969, 8591, 16393, 36736, 46529, 71839, 151823, 210625, 285039, 377609, 491071, 556544, 987049, 1480961, 1787983, 2542559, 2998849, 4092713, 6262319, 7148041, 8648704, 10374079, 13061231, 14585473, 19964959, 22051521, 24297503, 32072129, 45172609, 53055401, 57362863, 66759119
Offset: 1

Views

Author

N. J. A. Sloane, Oct 05 2013

Keywords

Crossrefs

A229740 a(n) = q^9/6+5*q^8/6+2*q^7/3-q^6/6-5*q^5/6+q^4/3 where q = n-th prime power A000961(n).

Original entry on oeis.org

1, 352, 9909, 107776, 698125, 12045817, 37679104, 103495401, 584190541, 2487920149, 15207694336, 25846158097, 68520305701, 367691205289, 766959765625, 1513188079677, 2846113596901, 5135516500321, 6803021627392, 24650159312557, 61346708983561, 93685639700269, 206700247118737, 299545983486001
Offset: 1

Views

Author

N. J. A. Sloane, Oct 05 2013

Keywords

Crossrefs

Showing 1-4 of 4 results.