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A124145 a(1)=1, a(2)=2, a(n)=smallest number greater than a(n-1) that can be written as sum of consecutive earlier terms in exactly one way. 2
1, 2, 3, 5, 6, 8, 10, 16, 17, 18, 19, 22, 25, 26, 29, 32, 33, 37, 40, 41, 43, 45, 47, 48, 50, 54, 55, 57, 59, 62, 66, 67, 68, 69, 73, 75, 76, 77, 81, 83, 85, 86, 87, 95, 98, 99, 101, 105, 109, 117, 118, 120, 126, 128, 129, 131, 133, 134, 137, 139, 140, 141, 143, 146, 148 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
This sequence is similar to the Hofstadter sequence A005243 except the decomposition into summands has to be unique.
This sequence has similarities with Ulam numbers (A002858); here we consider unique sums of consecutive terms, there unique sums of two distinct terms. - Rémy Sigrist, Jan 02 2022
LINKS
Charles R Greathouse IV, Table of n, a(n) for n = 1..1000
EXAMPLE
a(7)=10 because 2+3+5=10 is the only way to sum up consecutive terms. 11 is not contained in the sequence because 11=5+6=1+2+3+5 has got more than one decompositions.
PROG
(PARI) See Links section.
CROSSREFS
Sequence in context: A118053 A252482 A348868 * A188064 A104424 A028806
KEYWORD
easy,nonn
AUTHOR
Tobias Baumann (baumtobi(AT)students.uni-mainz.de), Dec 01 2006
STATUS
approved

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Last modified March 29 09:59 EDT 2024. Contains 371268 sequences. (Running on oeis4.)