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.

A361143 E.g.f. satisfies A(x) = exp( x*A(x)^4/(1 - x*A(x)^2) ).

Original entry on oeis.org

1, 1, 11, 241, 8105, 370061, 21403675, 1500521485, 123685912817, 11724012791929, 1256517775425131, 150254377493878505, 19833528195709809817, 2864566162751107839493, 449364739762263286489403, 76084967168410028438252101, 13829896583435315152843525985
Offset: 0

Views

Author

Seiichi Manyama, Mar 02 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = n!*sum(k=0, n, (2*n+2*k+1)^(k-1)*binomial(n-1, n-k)/k!);

Formula

a(n) = n! * Sum_{k=0..n} (2*n+2*k+1)^(k-1) * binomial(n-1,n-k)/k!.

A363357 E.g.f. satisfies A(x) = exp(x * A(x)^2 * (1 + x * A(x))).

Original entry on oeis.org

1, 1, 7, 85, 1581, 39501, 1244953, 47426373, 2120506489, 108894505753, 6317267871501, 408637512353049, 29164082035045477, 2276557391070945477, 192956160476285907457, 17647873882378895267821, 1732445579330211460781937, 181694902682241512454842673
Offset: 0

Views

Author

Seiichi Manyama, Aug 17 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = n!*sum(k=0, n, (n+k+1)^(k-1)*binomial(k, n-k)/k!);

Formula

a(n) = n! * Sum_{k=0..n} (n+k+1)^(k-1) * binomial(k,n-k)/k!.

A364942 E.g.f. satisfies A(x) = exp( x*A(x)^2 / (1 - x*A(x))^3 ).

Original entry on oeis.org

1, 1, 11, 193, 5037, 176221, 7755433, 411995529, 25665442841, 1835264297881, 148192928581581, 13338664928207389, 1324344628799752981, 143792046846092303829, 16949599953405295395521, 2155710634160924802161041, 294250014166281073851809457
Offset: 0

Views

Author

Seiichi Manyama, Aug 14 2023

Keywords

Crossrefs

Programs

  • PARI
    a(n) = n!*sum(k=0, n, (n+k+1)^(k-1)*binomial(n+2*k-1, n-k)/k!);

Formula

a(n) = n! * Sum_{k=0..n} (n+k+1)^(k-1) * binomial(n+2*k-1,n-k)/k!.

A364941 E.g.f. satisfies A(x) = exp( x*A(x)^2 / (1 - x*A(x))^2 ).

Original entry on oeis.org

1, 1, 9, 139, 3201, 98861, 3842653, 180342471, 9926870145, 627296384665, 44766115252821, 3561306199330859, 312531347680052449, 29994317717748851013, 3125271184480991706189, 351360521075659460743471, 42395667639523579933634817, 5464885215245368415146646321
Offset: 0

Views

Author

Seiichi Manyama, Aug 14 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Join[{1}, Table[n! * Sum[(n+k+1)^(k-1) * Binomial[n+k-1,n-k]/k!, {k,0,n}], {n,1,20}]] (* Vaclav Kotesovec, Nov 18 2023 *)
  • PARI
    a(n) = n!*sum(k=0, n, (n+k+1)^(k-1)*binomial(n+k-1, n-k)/k!);

Formula

a(n) = n! * Sum_{k=0..n} (n+k+1)^(k-1) * binomial(n+k-1,n-k)/k!.
a(n) ~ s^2 * sqrt((1 + r*s)/(1 + 2*r*s^2 - 3*r^2*s^2 + 2*r^3*s^3)) * n^(n-1) / (exp(n) * r^(n - 1/2)), where r = 0.1208150626316801846776206051780724146363... and s = 1.505405324736640697527292770220289316454393380356... are real roots of the system of equations exp(r*s^2 / (1 - r*s)^2) = s, 2*r*s^2 = (1 - r*s)^3. - Vaclav Kotesovec, Nov 18 2023

A365014 E.g.f. satisfies A(x) = exp( x*A(x)^2/(1 - x * A(x)^3) ).

Original entry on oeis.org

1, 1, 7, 103, 2349, 72961, 2874793, 137399487, 7724650601, 499542475105, 36532938744621, 2981405776356679, 268605245211618637, 26480489709604968129, 2835590837094928349921, 327748240537910056251151, 40669893396736296241364817, 5392699633877586027282801217
Offset: 0

Views

Author

Seiichi Manyama, Aug 15 2023

Keywords

Crossrefs

Programs

  • Mathematica
    Array[#!*Sum[ (3 # - k + 1)^(k - 1)*Binomial[# - 1, # - k]/k!, {k, 0, #}] &, 18, 0] (* Michael De Vlieger, Aug 18 2023 *)
  • PARI
    a(n) = n!*sum(k=0, n, (3*n-k+1)^(k-1)*binomial(n-1, n-k)/k!);

Formula

a(n) = n! * Sum_{k=0..n} (3*n-k+1)^(k-1) * binomial(n-1,n-k)/k!.
Showing 1-5 of 5 results.