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A129731 Each term is the previous term times the number of letters in the previous number, as conventionally spelled out in English. 0
1, 3, 15, 105, 1470, 42630, 1364160, 75028800, 3676411200, 272054428800 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Multiplicative analog of A060403.

LINKS

Table of n, a(n) for n=1..10.

FORMULA

a(0) = 1; a(n+1) = a(n) * A005589(a(n)). a(0) = 1; a(n+1) = PRODUCT[i=1..n] A005589(a(i)).

EXAMPLE

a(1) = 1.

a(2) = 1 * A060403(1) = 1 * LettersIn("one") = 1*3 = 3.

a(3) = 3 * A060403(2) = 3 * LettersIn("three") = 3*5 = 15.

a(4) = 15 * A060403(3) = 15 * LettersIn("fifteen") = 15*7 = 105.

a(10) = 74 * A060403(a(9)) = 74 * LettersIn("three billion six hundred seventysix million four hundred eleven thousand two hundred") = 1364160 * 55 * 49 * 74 = 272054 28800 = 2^7 * 3 * 5^2 * 7^4 * 11 * 29 * 37.

CROSSREFS

Cf. A005589, A060403.

Sequence in context: A118750 A070826 A048599 * A269455 A088109 A231634

Adjacent sequences:  A129728 A129729 A129730 * A129732 A129733 A129734

KEYWORD

easy,nonn,word,dumb,less

AUTHOR

Jonathan Vos Post, May 12 2007, May 22 2007

STATUS

approved

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Last modified November 19 12:38 EST 2018. Contains 317351 sequences. (Running on oeis4.)