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 1-5 of 5 results.

A163146 a(n) = 12*a(n-1)-31*a(n-2) for n > 1; a(0) = 1, a(1) = 11.

Original entry on oeis.org

1, 11, 101, 871, 7321, 60851, 503261, 4152751, 34231921, 282047771, 2323383701, 19137123511, 157620587401, 1298196219971, 10692116430221, 88061314343551, 725280162785761, 5973461208779051, 49197849458990021, 405196896035729671
Offset: 0

Views

Author

Klaus Brockhaus, Jul 21 2009

Keywords

Comments

Binomial transform of A093145 without initial 0. Inverse binomial transform of A163147.

Crossrefs

Programs

  • Magma
    [ n le 2 select 10*n-9 else 12*Self(n-1)-31*Self(n-2): n in [1..20] ];
  • Mathematica
    LinearRecurrence[{12,-31},{1,11},20] (* Harvey P. Dale, Apr 15 2019 *)

Formula

a(n) = ((1+sqrt(5))*(6+sqrt(5))^n+(1-sqrt(5))*(6-sqrt(5))^n)/2.
G.f.: (1-x)/(1-12*x+31*x^2).

A361290 Square array T(n,k), n >= 0, k >= 0, read by antidiagonals downwards, where T(n,k) = Sum_{j=0..floor((n-1)/2)} k^(n-1-j) * binomial(n,2*j+1).

Original entry on oeis.org

0, 0, 1, 0, 1, 0, 0, 1, 2, 0, 0, 1, 4, 4, 0, 0, 1, 6, 14, 8, 0, 0, 1, 8, 30, 48, 16, 0, 0, 1, 10, 52, 144, 164, 32, 0, 0, 1, 12, 80, 320, 684, 560, 64, 0, 0, 1, 14, 114, 600, 1936, 3240, 1912, 128, 0, 0, 1, 16, 154, 1008, 4400, 11648, 15336, 6528, 256, 0
Offset: 0

Views

Author

Seiichi Manyama, Mar 11 2023

Keywords

Examples

			Square array begins:
  0,  0,   0,   0,    0,    0, ...
  1,  1,   1,   1,    1 ,   1, ...
  0,  2,   4,   6,    8,   10, ...
  0,  4,  14,  30,   52,   80, ...
  0,  8,  48, 144,  320,  600, ...
  0, 16, 164, 684, 1936, 4400, ...
		

Crossrefs

Column k=1..10 give A131577, A007070(n-1), A030192(n-1), A016129(n-1), A093145, A154237, A154248, A154348(n-1), A016175(n-1), A361293.
Main diagonal gives A360766.
Cf. A361432.

Programs

  • PARI
    T(n, k) = polcoef(lift(Mod('x, ('x-k)^2-k)^n), 1);

Formula

T(0,k) = 0, T(1,k) = 1; T(n,k) = 2 * k * T(n-1,k) - (k-1) * k * T(n-2,k).
T(n,k) = ((k + sqrt(k))^n - (k - sqrt(k))^n)/(2 * sqrt(k)) for k > 0.
G.f. of column k: x/(1 - 2 * k * x + (k-1) * k * x^2).
E.g.f. of column k: exp(k * x) * sinh(sqrt(k) * x) / sqrt(k) for k > 0.

A162769 a(n) = ((1+sqrt(5))*(4+sqrt(5))^n + (1-sqrt(5))*(4-sqrt(5))^n)/2.

Original entry on oeis.org

1, 9, 61, 389, 2441, 15249, 95141, 593389, 3700561, 23077209, 143911501, 897442709, 5596515161, 34900251489, 217640345141, 1357219994749, 8463716161441, 52780309349289, 329141597018461, 2052549373305509
Offset: 0

Views

Author

Al Hakanson (hawkuu(AT)gmail.com), Jul 13 2009

Keywords

Comments

Binomial transform of A082762. Fourth binomial transform of A162962. Inverse binomial transform of A093145 without initial 0.

Crossrefs

Programs

  • Magma
    Z:=PolynomialRing(Integers()); N:=NumberField(x^2-5); S:=[ ((1+r)*(4+r)^n+(1-r)*(4-r)^n)/2: n in [0..19] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Jul 19 2009
  • Mathematica
    f[n_] := Block[{s = Sqrt@ 5}, Simplify[((1 + s)(4 + s)^n + (1 - s)(4 - s)^n)/2]]; Array[f, 21, 0] (* Or *)
    a[n_] := 8 a[n - 1] - 11 a[n - 2]; a[0] = 1; a[1] = 9; Array[a, 22, 0] (* Or *)
    CoefficientList[Series[(1 + x)/(1 - 8 x + 11 x^2), {x, 0, 21}], x] (* Robert G. Wilson v *)

Formula

a(n) = 8*a(n-1) - 11*a(n-2) for n > 1; a(0) = 1, a(1) = 9.
G.f.: (1+x)/(1-8*x+11*x^2).
a(n) = A091870(n)+A091870(n+1). - R. J. Mathar, Feb 04 2021

Extensions

Edited and extended beyond a(5) by Klaus Brockhaus, Jul 19 2009

A162962 a(n) = 5*a(n-2) for n > 2; a(1) = 1, a(2) = 5.

Original entry on oeis.org

1, 5, 5, 25, 25, 125, 125, 625, 625, 3125, 3125, 15625, 15625, 78125, 78125, 390625, 390625, 1953125, 1953125, 9765625, 9765625, 48828125, 48828125, 244140625, 244140625, 1220703125, 1220703125, 6103515625, 6103515625, 30517578125
Offset: 1

Views

Author

Klaus Brockhaus, Jul 19 2009

Keywords

Comments

Apparently a(n) = A074872(n+1), a(n) = A056451(n-1) for n > 1.
Binomial transform is A084057 without initial 1, second binomial transform is A048876, third binomial transform is A082762, fourth binomial transform is A162769, fifth binomial transform is A093145 without initial 0.

Crossrefs

Cf. A000351 (powers of 5), A074872 (powers of 5 repeated), A056451 (5^floor((n+1)/2)), A084057, A048876, A082762, A162769, A093145.

Programs

  • Magma
    [ n le 2 select 4*n-3 else 5*Self(n-2): n in [1..30] ];
  • Mathematica
    LinearRecurrence[{0,5},{1,5},30] (* Harvey P. Dale, Mar 18 2023 *)

Formula

a(n) = 5^((1/4)*(2*n-1+(-1)^n)).
G.f.: x*(1+5*x)/(1-5*x^2).

A360766 a(0) = 0; a(n) = ( (n + sqrt(n))^n - (n - sqrt(n))^n )/(2 * sqrt(n)).

Original entry on oeis.org

0, 1, 4, 30, 320, 4400, 73872, 1462552, 33325056, 858283776, 24641000000, 779935205984, 26972930949120, 1011642325897216, 40890444454377728, 1771640957790000000, 81896889467638120448, 4022826671022707900416, 209224123984489179202560
Offset: 0

Views

Author

Seiichi Manyama, Mar 11 2023

Keywords

Crossrefs

Main diagonal of A361290.
Cf. A084062.

Programs

  • PARI
    a(n) = polcoeff(lift(Mod('x, ('x-n)^2-n)^n), 1); \\ Kevin Ryde, Mar 16 2023

Formula

a(n) = Sum_{k=0..floor((n-1)/2)} n^(n-1-k) * binomial(n,2*k+1).
a(n) = [x^n] x/(1 - 2*n*x + (n-1)*n*x^2).
a(n) = n! * [x^n] exp(n * x) * sinh(sqrt(n) * x) / sqrt(n) for n > 0.
Showing 1-5 of 5 results.