cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-6 of 6 results.

A055162 The number n has digits in ascending order and n=a-b where a has the digits of n in descending order and b has the digits of n in another order (a and b perhaps with extra zeros), ordered by a.

Original entry on oeis.org

459, 1467, 445599, 134667, 13346667, 1245789, 123456789, 444555999, 1333466667, 123456789, 12457899, 12334566789, 133334666667, 12334566789, 1234567899, 124578999, 444455559999, 1233345666789
Offset: 1

Views

Author

Henry Bottomley, Apr 27 2000

Keywords

Comments

Each term of this sequence A055162(n) corresponds to A099009(n+1), with its digits being reordered in the ascending manner. - Alexander R. Povolotsky, Apr 26 2012
All terms of this sequence are divisible by nine, yielding 51, 163, 49511, 14963, 1482963,.... - Alexander R. Povolotsky, Apr 29 2012

Examples

			459 = 954 - 495.
		

References

  • Denis Borris, Ken Duisenberg's Puzzle of the Week, April 20, 2000

Crossrefs

Formula

a(n) = A055161(n) - A055160(n).

A055160 Numbers n with the property that n=a-b where a has the digits of n in descending order and b has the digits of n in ascending order (perhaps with leading zeros), ordered by a.

Original entry on oeis.org

495, 6174, 549945, 631764, 63317664, 97508421, 864197532, 554999445, 6333176664, 9753086421, 9975084201, 86431976532, 633331766664, 975330866421, 997530864201, 999750842001, 555499994445, 8643319766532
Offset: 1

Views

Author

Henry Bottomley, Apr 27 2000

Keywords

Comments

This sequence appears to differ from A099009 at the positions of two terms in it: 554999445 and 555499994445. - Alexander R. Povolotsky, May 01 2012

Examples

			495 = 954-459.
		

References

  • Denis Borris, Ken Duisenberg's Puzzle of the Week, April 20, 2000

Crossrefs

Formula

a(n) = A055161(n) - A055162(n).

A055158 n has distinct digits in descending order and n=a+b where a has the digits of n in another order and b has the digits of n in ascending order (perhaps with leading zeros).

Original entry on oeis.org

954, 7641, 98754210, 987654321, 9876543210
Offset: 0

Views

Author

Henry Bottomley, Apr 27 2000

Keywords

Examples

			954=495+459
		

References

  • Denis Borris, Ken Duisenberg's Puzzle of the Week, April 20, 2000

Crossrefs

Cf. A055161.

Formula

a(n)= A055157(n)+A055159(n)

A121969 Numbers k such that if you subtract k-reversed from k you get a natural number with the same digits as k.

Original entry on oeis.org

954, 1980, 2961, 3870, 5823, 7641, 9108, 19980, 29880, 29961, 32760, 38970, 39780, 49680, 49842, 54270, 58923, 59580, 60273, 60732, 69462, 69480, 69723, 70254, 73260, 76941, 79344, 79380, 89226, 89280, 89604, 90810, 91908, 96732, 99108
Offset: 1

Views

Author

Tanya Khovanova, Sep 04 2006

Keywords

Examples

			954 - 459 = 495, 19980 - 8991 = 10989.
		

References

  • David Wells, The Penguin Dictionary of Curious and Interesting Numbers (Rev. ed. 1997), p. 154 (entry for 1980).

Crossrefs

Cf. A055161.

Programs

  • Mathematica
    srdQ[n_]:=Module[{idn=IntegerDigits[n],rn},rn=FromDigits[Reverse[idn]];n>rn&&Sort[IntegerDigits[n-rn]]==Sort[idn]]; Select[Range[100000], srdQ] (* Harvey P. Dale, Jun 21 2013 *)
  • PARI
    isok(n) = {my(d = digits(n)); diff = my(n - subst(Polrev(d), x, 10)); (diff > 0) && (vecsort(digits(diff)) == vecsort(d));} \\ Michel Marcus, Sep 04 2015

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

Original entry on oeis.org

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

Views

Author

Tanya Khovanova, Sep 04 2006

Keywords

Comments

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

Examples

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

Crossrefs

Programs

  • 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 *)

A331468 Lexicographically earliest sequence of distinct triples (A,B,C) such that A + B = C with A, B, C anagrams of each other and A < B.

Original entry on oeis.org

459, 495, 954, 1089, 8019, 9108, 1089, 8091, 9180, 1269, 1692, 2961, 1467, 6147, 7614, 1467, 6174, 7641, 1476, 4671, 6147, 1503, 3510, 5013, 1530, 3501, 5031, 1746, 4671, 6417, 2385, 2853, 5238, 2439, 2493, 4932, 2502, 2520, 5022, 2538, 3285, 5823, 2691, 6921, 9612, 2853, 5382, 8235, 3285, 5238, 8523
Offset: 1

Views

Author

Eric Angelini and Gilles Esposito-Farèse, Jan 17 2020

Keywords

Comments

The sequence is infinite as (10*A,10*B,10*C) is a legal triple if (A,B,C) is a legal triple.
From Bernard Schott, Jan 19 2020: (Start)
Theorem: Every term of this sequence is divisible by 9.
Proof: If m = digsum(A) = digsum(B) = digsum(C) where digsum = A007953, then A + B = C implies digsum(A) + digsum(B) == digsum(C) (mod 9), so 2*m == m (mod 9) and m == 0 (mod 9). (End)
The numbers of 3-digit to 8-digit triples are: 1, 25, 648, 17338, 495014, and 17565942. - Hans Havermann, Feb 02 2020

Examples

			The first triple is (459,495,954) and we have 459 + 495 = 954, anagrams of each other;
The second triple is (1089,8019,9108) and we have 1089 + 8019 = 9108, anagrams of each other;
The third triple is (1089,8091,9180) and we have 1089 + 8091 = 9180, anagrams of each other;
The fourth triple is (1269,1692,2961) and we have 1269 +1692 = 2961, anagrams of each other; etc.
		

Crossrefs

Showing 1-6 of 6 results.