A134877 -id:A134877 - cp's OEIS frontend

A134878 Decimal expansion of Sum_{k>=1} 1/(k^2)^(k^2).

1, 0, 0, 3, 9, 0, 6, 2, 5, 2, 5, 8, 1, 1, 7, 4, 7, 9, 1, 7, 6, 7, 4, 0, 7, 2, 9, 0, 6, 1, 4, 3, 0, 6, 7, 4, 1, 0, 7, 6, 1, 2, 4, 9, 2, 4, 3, 7, 9, 2, 8, 5, 9, 4, 7, 8, 7, 6, 4, 0, 4, 7, 9, 0, 7, 9, 5, 0, 9, 9, 2, 1, 9, 0, 5, 0, 8, 6, 9, 4, 4, 5, 1, 6, 6, 8, 8, 4, 0, 2, 7, 3, 4, 8, 3, 4, 4, 6, 9, 6, 6, 8, 8, 5

Offset: 1

Artur Jasinski, Nov 14 2007

Sum_{k>=1} 1/(k^2)^(k^2) = 1.003906252581174791767407290614306741076124924379285...

Cf. A073009, A100085, A134877.

RealDigits[N[Sum[1/(n^2)^(n^2), {n, 1, 30}], 200]][[1]]

Equals Sum_{n>=1} 1/A008972(n). - R. J. Mathar, Jul 31 2025

A134879 Decimal expansion of Sum_{k>=1} 1/(k^3)^(k^3).

Original entry on oeis.org

1, 0, 0, 0, 0, 0, 0, 0, 5, 9, 6, 0, 4, 6, 4, 4, 7, 7, 5, 3, 9, 0, 6, 2, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 5, 5, 1, 6, 5, 2, 3, 3, 7, 2, 8, 4, 5, 8, 8, 8, 8, 8, 3, 7, 9, 8, 9, 7, 5, 9, 3, 7, 6, 8, 3, 7, 2, 0, 8, 4, 9, 2, 0, 2, 8, 5, 0, 1, 1, 5, 8, 4, 6, 2, 0, 8, 2, 0, 3, 7, 4, 9, 4, 4, 6, 3, 3, 8, 5, 6, 0, 8, 4, 0, 0

Offset: 1

Artur Jasinski, Nov 14 2007

Sum_{k>=1} 1/(k^3)^(k^3) = 1.00000005960464477539062500000000000000225516523372...

Cf. A073009, A100085, A134877, A134878.

RealDigits[N[Sum[1/(n^3)^(n^3), {n, 1, 30}], 200]][[1]]

suminf(n=1,n^(-3*n^3)) \\ Charles R Greathouse IV, Dec 26 2011

A134880 Decimal expansion of Sum_{k>=1} 1/(2^k)^(2^k).

Original entry on oeis.org

2, 5, 3, 9, 0, 6, 3, 0, 9, 6, 0, 4, 6, 4, 4, 7, 7, 5, 4, 4, 4, 8, 3, 5, 1, 0, 8, 6, 2, 4, 2, 7, 5, 2, 2, 1, 7, 0, 0, 3, 7, 2, 6, 4, 0, 0, 4, 4, 1, 8, 1, 3, 1, 3, 3, 3, 7, 0, 7, 2, 6, 6, 4, 5, 8, 5, 4, 1, 1, 9, 7, 7, 3, 3, 5, 5, 9, 0, 7, 7, 9, 3, 6, 0, 9, 7, 6, 6, 9, 0, 4, 0, 1

Offset: 0

Artur Jasinski, Nov 14 2007

			0.25390630960464477544483510862427522170037264004418131333707266458541197733559...

Cf. A073009, A100085, A134877, A134878, A134879.

RealDigits[N[Sum[1/(2^n)^(2^n), {n, 1, 30}], 200]][[1]]

suminf(k=1, 1/(2^k)^(2^k)) \\ Michel Marcus, Jan 15 2021

A134883 Decimal expansion of Sum_{n>=1} 1/(n^n+1).

Original entry on oeis.org

7, 3, 9, 9, 4, 7, 9, 4, 3, 4, 9, 5, 4, 6, 5, 5, 1, 2, 2, 5, 6, 0, 2, 5, 5, 3, 0, 7, 3, 4, 9, 9, 4, 7, 8, 2, 0, 5, 6, 1, 1, 0, 6, 6, 5, 7, 4, 2, 2, 4, 3, 9, 6, 2, 8, 7, 4, 5, 4, 5, 6, 5, 1, 9, 9, 9, 8, 0, 4, 3, 0, 8, 5, 4, 0, 8, 4, 8, 8, 1, 0, 2, 8, 9, 7, 3, 9, 5, 3, 1, 1, 2, 0, 7, 1, 2, 1, 5, 6, 8, 2, 0, 5, 9

Offset: 0

Artur Jasinski, Nov 15 2007

Constant formed from sum of reversed Sierpinski numbers of first kind A014566.

			0.7399479434954655122560255307349947820561106657422439628745456519998...

Cf. A014566, A073009, A100085, A134877, A134878, A134879, A134880, A134881, A134882.

RealDigits[N[Sum[1/(n^n + 1), {n, 1, 150}], 100]][[1]] (* first zero removed *)

A134881 Decimal expansion of Sum_{k>=1} 1/(e^k)^(e^k).

Original entry on oeis.org

0, 6, 5, 9, 8, 8, 4, 1, 7, 7, 4, 3, 3, 4, 3, 7, 9, 1, 7, 5, 6, 5, 6, 2, 3, 8, 6, 7, 2, 4, 1, 0, 7, 7, 9, 7, 4, 3, 8, 1, 4, 4, 4, 3, 9, 3, 4, 1, 2, 1, 3, 1, 0, 2, 6, 2, 8, 0, 5, 4, 3, 6, 6, 5, 5, 9, 9, 9, 8, 5, 2, 0, 7, 6, 6, 0, 7, 1, 5, 7, 1, 2, 7, 8, 5, 1, 1, 2, 0, 0, 8, 1, 9, 4, 3, 6, 0, 7, 7, 0, 2

Offset: 0

Artur Jasinski, Nov 14 2007

			0.06598841774334379175656238672410779743814443934121...

Cf. A073009, A100085, A134877, A134878, A134879, A134890.

RealDigits[N[Sum[1/(E^n)^(E^n), {n, 1, 20}], 200]][[1]] (* first two zeros removed *)

A134882 Decimal expansion of Sum_{x>=1} 1/(Pi^x)^(Pi^x).

Original entry on oeis.org

0, 2, 7, 4, 2, 5, 6, 9, 3, 2, 7, 6, 9, 9, 1, 3, 7, 8, 2, 8, 1, 1, 6, 1, 1, 9, 4, 8, 4, 3, 1, 2, 0, 8, 3, 2, 6, 8, 2, 2, 5, 5, 9, 5, 3, 8, 8, 0, 5, 7, 8, 9, 0, 7, 0, 9, 9, 8, 8, 1, 7, 4, 4, 3, 1, 0, 1, 6, 1, 3, 8, 6, 5, 0, 3, 8, 8, 4, 7, 4, 4, 5, 7, 6, 3, 0, 8, 4, 3, 8, 8, 3, 2, 9, 1, 7, 4, 4, 7, 1, 1

Offset: 0

Artur Jasinski, Nov 14 2007

			0.02742569327699137828116119484312083268225595388057...

Cf. A073009, A100085, A134877, A134878, A134879, A134880, A134881, A134883.

RealDigits[N[Sum[1/(Pi^n)^(Pi^n), {n, 1, 20}], 200]][[1]] (* first two zeros removed *)

A174212 Ultradoublefactorials: a(n) = (n!!)^(n!!).

Original entry on oeis.org

1, 1, 4, 27, 16777216, 437893890380859375, 500702078263459319174537025249570888246709955377400223021257741084821677152403456

Offset: 0

Paolo P. Lava & Giorgio Balzarotti, Mar 16 2010

The next term (a(8)) has 993 digits. - Harvey P. Dale, Aug 17 2017

			For n=4 the doublefactorial is n!! = 4*2 = 8 and a(n) = n!!^n!! = 8^8 = 16777216.

Cf. A006882, A046882, A134877, A165812.

P:=proc(i) local a,n; for n from 0 by 1 to i do print(doublefactorial(n)^doublefactorial(n)); od; end: P(10);

udf[n_]:=Module[{c=n!!},c^c]; Array[udf,7,0] (* Harvey P. Dale, Aug 17 2017 *)

a(n) = A006882(n)^A006882(n).

Sum_{n>=1} 1/a(n) = A134877. - Amiram Eldar, Nov 11 2020

cp's OEIS Frontend

A134878 Decimal expansion of Sum_{k>=1} 1/(k^2)^(k^2).

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A134879 Decimal expansion of Sum_{k>=1} 1/(k^3)^(k^3).

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A134880 Decimal expansion of Sum_{k>=1} 1/(2^k)^(2^k).

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A134883 Decimal expansion of Sum_{n>=1} 1/(n^n+1).

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A134881 Decimal expansion of Sum_{k>=1} 1/(e^k)^(e^k).

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A134882 Decimal expansion of Sum_{x>=1} 1/(Pi^x)^(Pi^x).

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A174212 Ultradoublefactorials: a(n) = (n!!)^(n!!).

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