OFFSET
1,3
COMMENTS
This pattern works whenever the adjacent digits of a number do not add to more than 9.
A059632(a(n)) = 11*a(n). - Reinhard Zumkeller, Jul 05 2014
REFERENCES
D. Wells, Curious and interesting numbers, Penguin Books, p. 156
LINKS
Reinhard Zumkeller, Table of n, a(n) for n = 1..10000
EXAMPLE
45*11=495 and 54*11=594, so 45 is a term.
PROG
(Haskell)
a039691 n = a039691_list !! (n-1)
a039691_list = filter (f 0) [0..] where
f d x = d' + d < 10 && (x < 10 || f d' x') where (x', d') = divMod x 10
-- Reinhard Zumkeller, Jul 05 2014
(PARI) isok(n) = my(d = digits(n), y = n*11); fromdigits(Vecrev(digits(y))) == fromdigits(Vecrev(d))*11; \\ Michel Marcus, Sep 05 2017
CROSSREFS
KEYWORD
easy,base,nonn
AUTHOR
EXTENSIONS
Offset corrected by Reinhard Zumkeller, Jul 05 2014
STATUS
approved