login
A121947
Positive numbers that are sums of proper substrings of their reversals.
1
149, 198, 1392, 16041957, 10000000009, 132324898229, 154879506575, 14501949763339, 15509886785307493, 16314428059046884, 1589868655913263939
OFFSET
1,1
COMMENTS
a(12) > 10^20. - Jon E. Schoenfield, Nov 15 2013
EXAMPLE
149 is in the sequence because 149 = 1 + 4 + 9 + 41 + 94.
MATHEMATICA
Select[Table[ n, {n, 10000000}], # == Plus @@ ToExpression[ Flatten[Table[ StringTake[StringReverse[ToString[ # ]], {i, j}], {i, StringLength[ToString[ # ]]}, {j, i, StringLength[ToString[ # ]]}]]] - ToExpression[StringReverse[ToString[ # ]]] &]
CROSSREFS
Cf. A121535.
Sequence in context: A209619 A031929 A161487 * A141946 A128390 A142029
KEYWORD
base,more,nonn
AUTHOR
Tanya Khovanova, Sep 04 2006
EXTENSIONS
a(4) from Donovan Johnson, Mar 30 2010
a(5) from Jon E. Schoenfield, Nov 12 2013
a(6) - a(11) from Jon E. Schoenfield, Nov 13 2013
STATUS
approved