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.

A170827 Sum of digits after the decimal point in the decimal expansion of (3/2)^n.

Original entry on oeis.org

0, 5, 7, 15, 13, 29, 25, 37, 38, 43, 42, 67, 60, 67, 60, 85, 73, 77, 71, 79, 95, 107, 106, 100, 95, 120, 95, 137, 143, 146, 138, 140, 147, 166, 172, 163, 172, 177, 180, 193, 158, 174, 171, 184, 177, 188, 188, 223, 212, 241, 213, 198, 243, 229, 236, 245, 278, 281, 305, 304
Offset: 0

Views

Author

Michel Lagneau, Dec 28 2009

Keywords

Comments

Some terms appear more than once, 60 being the first. - Robert G. Wilson v, Mar 10 2015

Examples

			1.0
1.5
2.25
3.375
5.0625
7.59375
11.390625
17.0859375
25.62890625

Links

Crossrefs

Cf. A002379, A170828.

Programs

  • Mathematica
    td[n_]:=Module[{rd=RealDigits[(3/2)^n]},Total[Drop[rd[[1]], rd[[2]]]]]; Array[td,60,0] (* Harvey P. Dale, Dec 13 2011 *)
  • PARI
    a(n) = sumdigits(lift(Mod(15,10^n)^n)) \\ Jianing Song, Sep 28 2022

Extensions

Edited by N. J. A. Sloane, Dec 28 2009

A204544 Fractional part of (3/2)^n without the decimal point.

Original entry on oeis.org

0, 5, 25, 375, 625, 59375, 390625, 859375, 62890625, 443359375, 6650390625, 49755859375, 746337890625, 6195068359375, 92926025390625, 893890380859375, 8408355712890625, 26125335693359375, 891880035400390625, 8378200531005859375, 25673007965087890625
Offset: 0

Views

Author

Michel Lagneau, Jan 16 2012

Keywords

Examples

			a(4) = 625 because (3/2)^4 = 5.0625.

References

  • G. Choquet, Répartition des nombres k(3/2)^n, mesures et ensembles associés, C.R. Acad. Sci. Paris, 290 (31 mars 1980), pp. 575-580.
  • G. Choquet, Construction effective de suites (k(3/2)^n). Etude des mesures (3/2)-stables, C.R. Acad. Sci. Paris, 291 (29 septembre 1980), pp. 69-74.

Links

Crossrefs

Cf. A170827, A170828.

Programs

  • Maple
    for n from 1 to 20 do: Digits:=30:x:= 1.5 ^n:y:=floor((x-floor(x))*10^n): printf(`%d, `,y):
od:
  • Mathematica
    Table[FractionalPart[(3/2)^n]*10^n, {n, 0, 30}] (* T. D. Noe, Jan 18 2012 *)

A171869 a(n) is the period of A175555(n) in the sequence {A175555}.

Original entry on oeis.org

1, 2, 2, 2, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, 524288, 1048576, 2097152, 4194304, 8388608, 16777216, 33554432, 67108864, 134217728, 268435456, 536870912, 1073741824, 2147483648, 4294967296
Offset: 1

Views

Author

Michel Lagneau, Dec 30 2009, Apr 22 2010

Keywords

Examples

			{A175555} = {5, 25, 375, 625, 59375, ...} =>
a(1) = 1 because A175555(1) = 5 occurs with the period 1 in the sequence A175555;
a(2) = 2 because A175555(2) = 25 occurs with the period 2 in the sequence A175555;
a(3) = 2 because A175555(3) = 375 occurs with the period 2 in the sequence A175555.

Crossrefs

Cf. A002379, A170828, A175555, A170827.

Programs

  • Maple
    nn:=2000:Digits:=nn:T:=array(1..nn):for n from 1 to nn do: T[n]:= irem(floor((1.5 ^n)*10^n),10^n): od: for a from 1 to nn do: z1:=T[a]: ii:=0:k:=0:for b from a+1 to nn while(ii)=0 do:k:=k+1:  z2:=irem(T[b],10^a): if z1=z2 then ii:=1:printf(`%d, `, k): else fi:od:od:

Formula

a(n) = 2^(n-4) if n > = 5.

Extensions

More terms and edits. - Michel Lagneau, Jul 14 2012
Showing 1-3 of 3 results.

Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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