Voozh

A078225

a(n) = A078221(n+1)/A078221(n).

3, 3, 11, 101, 10001, 100000001, 10000000000000001, 100000000000000000000000000000001, 10000000000000000000000000000000000000000000000000000000000000001

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OFFSET

1,1

LINKS

Table of n, a(n) for n=1..9.

FORMULA

a(n) = 10^(2^(n-3)) + 1, for n > 2.

Product_{n>=1} (1 - 1/a(n)) = 2/5. - Amiram Eldar, Dec 01 2025

MAPLE

A078221 := proc(n) if n =1 then 1 ; elif n = 2 then 3 ; else 10^(2^(n-3))-1 ; fi ; end: A078225 := proc(n) A078221(n+1)/A078221(n) ; end: for n from 1 to 20 do print(A078225(n)) ; od ; # R. J. Mathar, Feb 03 2007, using the formula for A078221

CROSSREFS

Cf. A078221, A078222, A078223, A078224.

Sequence in context: A350921 A352857 A352582 * A244247 A211346 A163372

Adjacent sequences: A078222 A078223 A078224 * A078226 A078227 A078228

KEYWORD

base,nonn

AUTHOR

Amarnath Murthy, Nov 23 2002

EXTENSIONS

More terms from R. J. Mathar, Feb 03 2007, using the formula for A078221

a(5) corrected by Max Alekseyev, Aug 21 2013

STATUS

approved

URL: https://oeis.org/A078225

⇱ A078225 - OEIS