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.

A255008 Array T(n,k) read by ascending antidiagonals, where T(n,k) is the numerator of polygamma(n, 1) - polygamma(n, k).

Original entry on oeis.org

0, 0, -1, 0, 1, -3, 0, -2, 5, -11, 0, 6, -9, 49, -25, 0, -24, 51, -251, 205, -137, 0, 120, -99, 1393, -2035, 5269, -49, 0, -720, 975, -8051, 22369, -256103, 5369, -363, 0, 5040, -5805, 237245, -257875, 14001361, -28567, 266681, -761, 0, -40320
Offset: 0

Views

Author

Jean-François Alcover, Feb 12 2015

Keywords

Comments

Up to signs, row n=0 is A001008/A002805, row n=1 is A007406/A007407 and column k=1 is n!.

Examples

			Array of fractions begin:
0,  -1,  -3/2,       -11/6,          -25/12,               -137/60, ...
0,   1,   5/4,       49/36,         205/144,             5269/3600, ...
0,  -2,  -9/4,    -251/108,       -2035/864,        -256103/108000, ...
0,   6,  51/8,    1393/216,      22369/3456,      14001361/2160000, ...
0, -24, -99/4,   -8051/324,   -257875/10368,   -806108207/32400000, ...
0, 120, 975/8, 237245/1944, 15187325/124416, 47463376609/388800000, ...
...
		

Crossrefs

Programs

  • Mathematica
    T[n_, k_] := (-1)^(n+1)*n!*HarmonicNumber[k-1, n+1] // Numerator; Table[T[n-k, k], {n, 0, 10}, {k, 1, n}] // Flatten

Formula

Fraction giving T(n,k) = polygamma(n, 1) - polygamma(n, k) = (-1)^(n+1)*n! * sum_{j=1..k-1} 1/j^(n+1) = (-1)^(n+1)*n!*H(k-1, n+1), where H(n,r) gives the n-th harmonic number of order r.

A370691 Square array read by upward antidiagonals: T(n, k) = denominator( 2*k!*(-2)^k*Sum_{m=1..n}( 1/(2*m-1)^(k+1) ) ).

Original entry on oeis.org

1, 1, 1, 3, 1, 1, 15, 9, 1, 1, 105, 225, 27, 1, 765765, 405810405, 91398648466125, 48049812916875, 1033788065625, 89339709375, 3796875, 729, 1, 1, 1, 315, 11025, 3375, 27, 1, 1, 3465, 99225, 1157625, 16875, 81, 1, 1, 45045, 12006225, 31255875, 40516875, 253125, 243, 1, 1, 45045, 2029052025
Offset: 0

Views

Author

Thomas Scheuerle, Apr 21 2024

Keywords

Examples

			array begins:
1,    1,        1,           1,              1,                  1
1,    1,        1,           1,              1,                  1
3,    9,        27,          27,             81,                 243
15,   225,      3375,        16875,          253125,             759375
105,  11025,    1157625,     40516875,       4254271875,         89339709375
315,  99225,    31255875,    3281866875,     1033788065625,      65128648134375
3465, 12006225, 41601569625, 48049812916875, 166492601756971875, 115379373017581509375
		

Crossrefs

Cf. A370692 (numerators),
Cf. A025547 (first column), A128492 (second column).
Cf. A128507.
Cf. A255008 (denominators polygamma(n, 1) - polygamma(n, k)).
Cf. A255009 (numerators polygamma(n, 1) - polygamma(n, k)).

Programs

  • Maple
    A := (n, k) -> Psi(k, n + 1/2) - Psi(k, 1/2):
    seq(lprint(seq(denom(A(n, k)), k = 0..4)), n=0..6);
  • PARI
    T(n, k) = denominator(sum(m=1, n, 1/(2*m-1)^(k+1))*k!*(-2)^k*2)

Formula

T(n, k) = denominator( polygamma(k, n + 1/2) - polygamma(k, 1/2) ).
T(n, k) = denominator( k!*(-1)^(k+1)*(zeta((k+1), 1/2 + n) - zeta((k+1), 1/2)) ), where zeta is the Hurwitz zeta function.
T(n, 0) = A025547(n).
T(n, 1) = A128492(n).
Conjectured: T(n, 2) = A128507(n).

A370692 Square array read by upward antidiagonals: T(n, k) = numerator( 2*k!*(-2)^k*Sum_{m=1..n}( 1/(2*m-1)^(k+1) ) ).

Original entry on oeis.org

0, 2, 0, 8, -4, 0, 46, -40, 16, 0, 352, -1036, 448, -96, 0, 1126, -51664, 56432, -2624, 768, 0, 13016, -469876, 19410176, -1642592, 62464, -7680, 0, 176138, -57251896, 524760752, -3945483392, 195262208, -1868800, 92160, 0, 176138, -57251896, 524760752, -3945483392, 195262208, -1868800, 92160
Offset: 0

Views

Author

Thomas Scheuerle, Apr 21 2024

Keywords

Examples

			array begins:
0,      0,        0,             0,                0
2,     -4,        16,           -96,               768
8,     -40,       448,          -2624,             62464
46,    -1036,     56432,        -1642592,          195262208
352,   -51664,    19410176,     -3945483392,       3281966329856
1126,  -469876,   524760752,    -319632174752,     797531263755008
13016, -57251896, 698956654912, -4680049729764032, 128444001508242193408
		

Crossrefs

Cf. A370691 (denominators).
Cf. A074599 (first column), A173945 (second column).
Cf. A255008 (denominators polygamma(n, 1) - polygamma(n, k)).
Cf. A255009 (numerators polygamma(n, 1) - polygamma(n, k)).

Programs

  • Maple
    A := (n, k) -> Psi(k, n + 1/2) - Psi(k, 1/2):
    seq(lprint(seq(numer(A(n, k)), k = 0..4)), n=0..6);  # Peter Luschny, Apr 22 2024
  • PARI
    T(n, k) = numerator(sum(m=1, n, 1/(2*m-1)^(k+1))*k!*(-2)^k*2)

Formula

T(n, k) = numerator( polygamma(k, n + 1/2) - polygamma(k, 1/2) ).
T(n, k) = numerator( k!*(-1)^(k+1)*(zeta((k+1), 1/2 + n) - zeta((k+1), 1/2)) ), where zeta is the Hurwitz zeta function.
T(n, 0) = A074599(n).
T(n, 1) = A173945(n+1).
Showing 1-3 of 3 results.