A121970 Numbers k such that if you subtract k from its reversal you get a positive number with the same digits as k.

459, 1467, 1692, 3285, 8019, 14967, 16992, 23706, 23769, 24894, 26496, 32796, 32985, 37206, 40698, 44397, 45207, 49599, 62298, 80199, 80919, 104697, 106992, 108729, 108972, 127809, 134667, 135378, 135774, 136818, 136962, 145827, 147492

Offset

1,1

Comments

If negative numbers are included then the sequence is the above together with its reversals. - Robert G. Wilson v, Sep 11 2006

Links

Harvey P. Dale, Table of n, a(n) for n = 1..1000

Kevin Browne, Subtracting the Reversal.

Example

459 is a member because 954 - 459 = 495; 16992 is a member because 29961 - 16992 = 12969.

Mathematica

Select[Table[n, {n, 200000}], ToExpression[StringReverse[ToString[ # ]]] - # > 0 && Sort[IntegerDigits[ # ]] == Sort[IntegerDigits[ToExpression[StringReverse[ToString[ # ]]] - # ]] &]
fQ[n_] := Block[{id = IntegerDigits@n}, rev = FromDigits@ Reverse@id; rev > n && Sort@id == Sort@IntegerDigits[rev - n]]; Select[ Range@153971, fQ@# &] (* Robert G. Wilson v, Sep 11 2006 *)
Select[Range[150000], With[{c=IntegerReverse[#]-#}, c>0&&Sort[IntegerDigits[c]]==Sort[IntegerDigits[#]]&]] (* Harvey P. Dale, Jun 07 2025 *)

Crossrefs

Cf. A055161, A121969.

Sequence in context: A160851 A124620 A224456 * A055162 A055159 A124694

Adjacent sequences: A121967 A121968 A121969 * A121971 A121972 A121973

Keyword

base,nonn

Author

Tanya Khovanova, Sep 04 2006

Status

approved