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

Rémy Sigrist, PARI program for A124145

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

KEYWORD

easy,nonn

AUTHOR

Tobias Baumann (baumtobi(AT)students.uni-mainz.de), Dec 01 2006

STATUS

approved