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A070152
Take pairs (x,y) with Sum_{j = x..y} j = concatenation of x and y. Sort pairs on y then x. This sequence gives x of each pair.
6
1, 2, 4, 13, 18, 33, 35, 7, 78, 133, 178, 228, 273, 388, 710, 1333, 1701, 1778, 2737, 3273, 3563, 3087, 3478, 12488, 13333, 14208, 17778, 31463, 36993, 5338, 7063, 9063, 12643, 15238, 17147, 22448, 23788, 27313, 29058, 34488, 36763, 38788, 43273, 50813, 53578
OFFSET
1,2
COMMENTS
From Bernard Schott, Jan 26 2022: (Start)
Some subsequences, from Diophante and Crux Mathematicorum:
{(2*10^m-5)/15, m >= 1} = 1, 13, 133, 1333, ... = A097166.
{2*(4*10^m+5)/45, m >= 1} = 2, 18, 178, 1778, ...
{13*(26*100^m-125)/12375, m >= 2} = 273, 27313, 2731313, ... (End)
LINKS
R. Hoshino, Astonishing Pairs of Numbers, Crux Mathematicorum 27(1), 2001, p. 39-44.
EXAMPLE
1+...+5 = 15; 2+...+7 = 27; 4+...+29 = 429; 13+...+53 = 1353; 18+...+63 = 1863.
133+...+533 = 133533.
273+...+2353 = 2732353.
CROSSREFS
Subsequence: A097166.
Sequence in context: A077319 A291901 A018701 * A176126 A240096 A018761
KEYWORD
nonn,base
AUTHOR
Lekraj Beedassy, May 06 2002
EXTENSIONS
More terms from David W. Wilson, Jun 04 2002
Name edited by Michel Marcus, Jan 29 2022
STATUS
approved