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A014938 a(1)=1, a(n) = n*21^(n-1) + a(n-1). 1
1, 43, 1366, 38410, 1010815, 25515421, 625878268, 15034586596, 355440320845, 8298240786655, 191776931546866, 4395106938053518, 100020864586079851, 2262634152933752305, 50921433140756382520, 1140878530467983299336 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
LINKS
FORMULA
G.f.: x/((1 - x)*(1 - 21*x)^2). - Stefano Spezia, Mar 11 2020
PROG
(PARI) a(n) = (1+21^n*(20*n-1))/400; \\ Jinyuan Wang, Mar 11 2020
CROSSREFS
Sequence in context: A214100 A229432 A122575 * A235646 A022220 A297028
KEYWORD
nonn,easy
AUTHOR
STATUS
approved

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Last modified May 25 09:14 EDT 2024. Contains 372786 sequences. (Running on oeis4.)