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.

A249078 E.g.f.: exp(1)*P(x) - Q(x), where P(x) = 1/Product_{n>=1} (1 - x^n/n) and Q(x) = Sum_{n>=1} 1/Product_{k=1..n} (k - x^k).

Original entry on oeis.org

1, 1, 4, 17, 96, 595, 4516, 37104, 351020, 3604001, 41007240, 502039444, 6703536516, 95376507135, 1459072099824, 23677731306350, 408821193129564, 7443839953433701, 143258713990271960, 2893053522512463984, 61396438056305204020, 1362146168353191078195, 31605702195327725326560
Offset: 0

Views

Author

Paul D. Hanna, Oct 28 2014

Keywords

Comments

The function P(x) = Product_{n>=1} 1/(1 - x^n/n) equals the e.g.f. of A007841, the number of factorizations of permutations of n letters into cycles in nondecreasing length order.

Examples

			E.g.f.: A(x) = 1 + x + 4*x^2/2! + 17*x^3/3! + 96*x^4/4! + 595*x^5/5! +...
such that A(x) = exp(1)*P(x) - Q(x), where
P(x) = 1/Product_{n>=1} (1 - x^n/n) = Sum_{n>=0} A007841(n)*x^n/n!, and
Q(x) = Sum_{n>=1} 1/Product_{k=1..n} (k - x^k).
More explicitly,
P(x) = 1/((1-x)*(1-x^2/2)*(1-x^3/3)*(1-x^4/4)*(1-x^5/5)*...);
Q(x) = 1/(1-x) + 1/((1-x)*(2-x^2)) + 1/((1-x)*(2-x^2)*(3-x^3)) + 1/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)) + 1/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)*(5-x^5)) +...
We can illustrate the initial terms a(n) in the following manner.
The coefficients in Q(x) = Sum_{n>=0} q(n)*x^n/n! begin:
q(0) = 1.7182818284590452...
q(1) = 1.7182818284590452...
q(2) = 4.1548454853771357...
q(3) = 12.901100113049497...
q(4) = 56.223782393706533...
q(5) = 285.72331242073065...
q(6) = 1801.2869693388211...
q(7) = 12727.542479311217...
q(8) = 104411.81066734227...
q(9) = 947120.40724315491...
and the coefficients in P(x) = 1/Product_{n>=1} (1 - x^n/n) begin:
A007841 = [1, 1, 3, 11, 56, 324, 2324, 18332, 167544, ...];
from which we can generate this sequence like so:
a(0) = exp(1)*1 - q(0) = 1;
a(1) = exp(1)*1 - q(1) = 1;
a(2) = exp(1)*3 - q(2) = 4;
a(3) = exp(1)*11 - q(3) = 17;
a(4) = exp(1)*56 - q(4) = 96;
a(5) = exp(1)*324 - q(5) = 595;
a(6) = exp(1)*2324 - q(6) = 4516;
a(7) = exp(1)*18332 - q(7) = 37104;
a(8) = exp(1)*167544 - q(8) = 351020; ...
		

Crossrefs

Programs

  • PARI
    \p100 \\ set precision
    {P=Vec(serlaplace(prod(k=1,31,1/(1-x^k/k +O(x^31)))));} \\ A007841
    {Q=Vec(serlaplace(sum(n=1,201,prod(k=1,n,1./(k-x^k +O(x^31))))));}
    for(n=0,30,print1(round(exp(1)*P[n+1]-Q[n+1]),", "))

A249474 E.g.f.: P(x)/exp(1) + Q(x), where P(x) = 1/Product_{n>=1} (1 - x^n/n) and Q(x) = Sum_{n>=1} -(-1)^n / Product_{k=1..n} (k - x^k).

Original entry on oeis.org

1, 1, 2, 7, 30, 169, 1128, 8700, 76494, 753139, 8182188, 97131376, 1256860330, 17470791933, 261284377168, 4164406202270, 70677340199670, 1268718107324255, 24091289738163140, 480954355282406340, 10097484764045220626, 221918808641500960217, 5103937368681669463800
Offset: 0

Views

Author

Paul D. Hanna, Oct 29 2014

Keywords

Comments

The function P(x) = Product_{n>=1} 1/(1 - x^n/n) equals the e.g.f. of A007841, the number of factorizations of permutations of n letters into cycles in nondecreasing length order.

Examples

			E.g.f.: A(x) = 1 + x + 2*x^2/2! + 7*x^3/3! + 30*x^4/4! + 169*x^5/5! +...
such that A(x) = exp(-1)*P(x) + Q(x), where
P(x) = 1/Product_{n>=1} (1 - x^n/n) = Sum_{n>=0} A007841(n)*x^n/n!, and
Q(x) = Sum_{n>=1} -(-1)^n / Product_{k=1..n} (k - x^k).
More explicitly,
P(x) = 1/((1-x)*(1-x^2/2)*(1-x^3/3)*(1-x^4/4)*(1-x^5/5)*...);
Q(x) = 1/(1-x) - 1/((1-x)*(2-x^2)) + 1/((1-x)*(2-x^2)*(3-x^3)) - 1/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)) + 1/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)*(5-x^5)) +-...
We can illustrate the initial terms a(n) in the following manner.
The coefficients in Q(x) = Sum_{n>=0} q(n)*x^n/n! begin:
q(0) = 0.632120558828557678...
q(1) = 0.632120558828557678...
q(2) = 0.896361676485673035...
q(3) = 2.953326147114134462...
q(4) = 9.398751294399229990...
q(5) = 49.80706106045268780...
q(6) = 273.0481787175680446...
q(7) = 1956.034084445119360...
q(8) = 14858.00690837186767...
q(9) = 137211.6953065362928...
and the coefficients in P(x) = 1/Product_{n>=1} (1 - x^n/n) begin:
A007841 = [1, 1, 3, 11, 56, 324, 2324, 18332, 167544, ...];
from which we can generate this sequence like so:
a(0) = exp(-1)*1 + q(0) = 1;
a(1) = exp(-1)*1 + q(1) = 1;
a(2) = exp(-1)*3 + q(2) = 2;
a(3) = exp(-1)*11 + q(3) = 7;
a(4) = exp(-1)*56 + q(4) = 30;
a(5) = exp(-1)*324 + q(5) = 169;
a(6) = exp(-1)*2324 + q(6) = 1128;
a(7) = exp(-1)*18332 + q(7) = 8700;
a(8) = exp(-1)*167544 + q(8) = 76494; ...
		

Crossrefs

Programs

  • PARI
    \p100 \\ set precision
    {P=Vec(serlaplace(prod(k=1, 31, 1/(1-x^k/k +O(x^31))))); } \\ A007841
    {Q=Vec(serlaplace(sum(n=1, 201, -(-1)^n * prod(k=1, n, 1./(k-x^k +O(x^31)))))); }
    for(n=0, 30, print1(round(exp(-1)*P[n+1]+Q[n+1]), ", "))

A249475 E.g.f.: exp(2)*P(x) - Q(x), where P(x) = 1/Product_{n>=1} (1 - x^n/n) and Q(x) = Sum_{n>=1} 2^n/Product_{k=1..n} (k - x^k).

Original entry on oeis.org

1, 1, 5, 25, 156, 1048, 8400, 72384, 710184, 7519240, 87797880, 1098513880, 14945280640, 216079283040, 3352657547680, 55071779464352, 961293645943680, 17669716422651776, 342988501737128576, 6978772157389361280, 149123855108936024576, 3328674238745847019520
Offset: 0

Views

Author

Paul D. Hanna, Oct 29 2014

Keywords

Comments

The function P(x) = Product_{n>=1} 1/(1 - x^n/n) equals the e.g.f. of A007841, the number of factorizations of permutations of n letters into cycles in nondecreasing length order.

Examples

			E.g.f.: A(x) = 1 + x + 5*x^2/2! + 25*x^3/3! + 156*x^4/4! + 1048*x^5/5! +...
such that A(x) = exp(2)*P(x) - Q(x), where
P(x) = 1/Product_{n>=1} (1 - x^n/n) = Sum_{n>=0} A007841(n)*x^n/n!, and
Q(x) = Sum_{n>=1} 2^n / Product_{k=1..n} (k - x^k).
More explicitly,
P(x) = 1/((1-x)*(1-x^2/2)*(1-x^3/3)*(1-x^4/4)*(1-x^5/5)*...);
Q(x) = 2/(1-x) + 2^2/((1-x)*(2-x^2)) + 2^3/((1-x)*(2-x^2)*(3-x^3)) + 2^4/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)) + 2^5/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)*(5-x^5)) +...
We can illustrate the initial terms a(n) in the following manner.
The coefficients in Q(x) = Sum_{n>=0} q(n)*x^n/n! begin:
q(0) = 6.3890560989306502272...
q(1) = 6.3890560989306502272...
q(2) = 17.167168296791950681...
q(3) = 56.279617088237152499...
q(4) = 257.78714154011641272...
q(5) = 1346.0541760535306736...
q(6) = 8772.1663739148311280...
q(7) = 63072.176405596679965...
q(8) = 527808.01503923686167...
q(9) = 4851990.6204200261720...
and the coefficients in P(x) = 1/Product_{n>=1} (1 - x^n/n) begin:
A007841 = [1, 1, 3, 11, 56, 324, 2324, 18332, 167544, ...];
from which we can generate this sequence like so:
a(0) = exp(2)*1 - q(0) = 1;
a(1) = exp(2)*1 - q(1) = 1;
a(2) = exp(2)*3 - q(2) = 5;
a(3) = exp(2)*11 - q(3) = 25;
a(4) = exp(2)*56 - q(4) = 156;
a(5) = exp(2)*324 - q(5) = 1048;
a(6) = exp(2)*2324 - q(6) = 8400;
a(7) = exp(2)*18332 - q(7) = 72384;
a(8) = exp(2)*167544 - q(8) = 710184; ...
		

Crossrefs

Programs

  • PARI
    \p100 \\ set precision
    {P=Vec(serlaplace(prod(k=1, 31, 1/(1-x^k/k +O(x^31))))); } \\ A007841
    {Q=Vec(serlaplace(sum(n=1, 201, 2^n * prod(k=1, n, 1./(k-x^k +O(x^31)))))); }
    for(n=0, 30, print1(round(exp(2)*P[n+1]-Q[n+1]), ", "))

A249480 E.g.f.: A(x,y) = exp(y)*P(x) - Q(x,y), where P(x) = 1/Product_{n>=1} (1 - x^n/n) and Q(x,y) = Sum_{n>=1} y^n / Product_{k=1..n} (k - x^k).

Original entry on oeis.org

1, 1, 0, 3, 1, 0, 11, 5, 1, 0, 56, 32, 7, 1, 0, 324, 204, 57, 9, 1, 0, 2324, 1604, 487, 89, 11, 1, 0, 18332, 13292, 4441, 897, 128, 13, 1, 0, 167544, 127224, 44712, 9864, 1486, 174, 15, 1, 0, 1674264, 1311384, 485592, 111744, 18486, 2286, 227, 17, 1, 0, 18615432, 14986632, 5735616, 1393872, 240318, 31734, 3329, 287, 19, 1, 0
Offset: 0

Views

Author

Paul D. Hanna, Nov 02 2014

Keywords

Comments

The function P(x) = Product_{n>=1} 1/(1 - x^n/n) equals the e.g.f. of A007841, the number of factorizations of permutations of n letters into cycles in nondecreasing length order.

Examples

			 Triangle begins:
1;
1, 0;
3, 1, 0;
11, 5, 1, 0;
56, 32, 7, 1, 0;
324, 204, 57, 9, 1, 0;
2324, 1604, 487, 89, 11, 1, 0;
18332, 13292, 4441, 897, 128, 13, 1, 0;
167544, 127224, 44712, 9864, 1486, 174, 15, 1, 0;
1674264, 1311384, 485592, 111744, 18486, 2286, 227, 17, 1, 0;
18615432, 14986632, 5735616, 1393872, 240318, 31734, 3329, 287, 19, 1, 0;
223686792, 183769992, 72550296, 18223632, 3296958, 455742, 51009, 4647, 354, 21, 1, 0;
2937715296, 2458713696, 993598248, 257587416, 48076704, 6958656, 801880, 77896, 6272, 428, 23, 1, 0;
41233157952, 35006137152, 14438206776, 3835359192, 738870048, 110022696, 13300084, 1330300, 114164, 8236, 509, 25, 1, 0; ...
GENERATING FUNCTION.
G.f.: A(x,y) = 1 + (1)*x + (3 + y)*x^2/2! + (11 + 5*y + y^2)*x^3/3! +
(56 + 32*y + 7*y^2 + y^3)*x^4/4! +
(324 + 204*y + 57*y^2 + 9*y^3 + y^4)*x^5/5! +
(2324 + 1604*y + 487*y^2 + 89*y^3 + 11*y^4 + y^5)*x^6/6! +...
such that
A(x,y) = exp(y)*P(x) - Q(x,y)
where
P(x) = 1/Product_{n>=1} (1 - x^n/n) = Sum_{n>=0} A007841(n)*x^n/n!, and
Q(x,y) = Sum_{n>=1} y^n / Product_{k=1..n} (k - x^k).
More explicitly,
P(x) = 1/((1-x)*(1-x^2/2)*(1-x^3/3)*(1-x^4/4)*(1-x^5/5)*...)
Q(x,y) = y/(1-x) + y^2/((1-x)*(2-x^2)) + y^3/((1-x)*(2-x^2)*(3-x^3)) + y^4/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)) + y^5/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)*(5-x^5)) +...
Column zero of this triangle forms the e.g.f. of A007841:
P(x) = 1 + x + 3*x^2/2! + 11*x^3/3! + 56*x^4/4! + 324*x^5/5! + 2324*x^6/6! + 18332*x^7/7! + 167544*x^8/8! +...
		

Crossrefs

Programs

  • PARI
    {T(n,k)=local(A=1, P=((prod(j=1, n+1, 1/(1 - x^j/j +x^2*O(x^n))))),
    Q=((sum(m=1, n+1, y^m * prod(j=1, m, 1/(j - x^j +x^2*O(x^n)))))) );
    A=exp(y)*P - Q; n!*polcoeff(polcoeff(A,n,x),k,y)}
    for(n=0,12,for(k=0,n,print1(T(n,k),", "));print(""))

A249476 E.g.f.: exp(3)*P(x) - Q(x), where P(x) = 1/Product_{n>=1} (1 - x^n/n) and Q(x) = Sum_{n>=1} 3^n/Product_{k=1..n} (k - x^k).

Original entry on oeis.org

1, 1, 6, 35, 242, 1773, 15056, 136652, 1393722, 15257919, 183206388, 2347929936, 32602306542, 479885400177, 7563888117504, 125952344438838, 2225653414414386, 41351620513521627, 810520833521436732, 16633643598838880244, 358221783030360367014, 8051927483267030640573
Offset: 0

Views

Author

Paul D. Hanna, Oct 29 2014

Keywords

Comments

The function P(x) = Product_{n>=1} 1/(1 - x^n/n) equals the e.g.f. of A007841, the number of factorizations of permutations of n letters into cycles in nondecreasing length order.

Examples

			E.g.f.: A(x) = 1 + x + 6*x^2/2! + 35*x^3/3! + 242*x^4/4! + 1773*x^5/5! +...
such that A(x) = exp(3)*P(x) - Q(x), where
P(x) = 1/Product_{n>=1} (1 - x^n/n) = Sum_{n>=0} A007841(n)*x^n/n!, and
Q(x) = Sum_{n>=1} 3^n / Product_{k=1..n} (k - x^k).
More explicitly,
P(x) = 1/((1-x)*(1-x^2/2)*(1-x^3/3)*(1-x^4/4)*(1-x^5/5)*...);
Q(x) = 3/(1-x) + 3^2/((1-x)*(2-x^2)) + 3^3/((1-x)*(2-x^2)*(3-x^3)) + 3^4/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)) + 3^5/((1-x)*(2-x^2)*(3-x^3)*(4-x^4)*(5-x^5)) +...
We can illustrate the initial terms a(n) in the following manner.
The coefficients in Q(x) = Sum_{n>=0} q(n)*x^n/n! begin:
q(0) = 19.085536923187667740...
q(1) = 19.085536923187667740...
q(2) = 54.256610769563003222...
q(3) = 185.94090615506434515...
q(4) = 882.79006769850939349...
q(5) = 4734.7139631128043480...
q(6) = 31622.787809488139829...
q(7) = 231556.06287587632502...
q(8) = 1971489.1982585546039...
q(9) = 18370572.391163877342...
and the coefficients in P(x) = 1/Product_{n>=1} (1 - x^n/n) begin:
A007841 = [1, 1, 3, 11, 56, 324, 2324, 18332, 167544, ...];
from which we can generate this sequence like so:
a(0) = exp(3)*1 - q(0) = 1;
a(1) = exp(3)*1 - q(1) = 1;
a(2) = exp(3)*3 - q(2) = 6;
a(3) = exp(3)*11 - q(3) = 35;
a(4) = exp(3)*56 - q(4) = 242;
a(5) = exp(3)*324 - q(5) = 1773;
a(6) = exp(3)*2324 - q(6) = 15056;
a(7) = exp(3)*18332 - q(7) = 136652;
a(8) = exp(3)*167544 - q(8) = 1393722; ...
		

Crossrefs

Programs

  • PARI
    \p100 \\ set precision
    {P=Vec(serlaplace(prod(k=1, 31, 1/(1-x^k/k +O(x^31))))); } \\ A007841
    {Q=Vec(serlaplace(sum(n=1, 201, 3^n * prod(k=1, n, 1./(k-x^k +O(x^31)))))); }
    for(n=0, 30, print1(round(exp(3)*P[n+1]-Q[n+1]), ", "))
Showing 1-5 of 5 results.