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 1-5 of 5 results.

A136614 Sum of digits of A108773 and of A136613.

Original entry on oeis.org

0, 2, 4, 6, 8, 10, 12, 14, 16, 18, 2, 4, 6, 8, 10, 12, 14, 16, 18, 11, 4, 6, 8, 10, 12, 14, 16, 18, 11, 13, 6, 8, 10, 12, 14, 16, 18, 11, 13, 15, 8, 10, 12, 14, 16, 18, 11, 13, 15, 17, 10, 12, 14, 16, 18, 11, 13, 15, 17, 19, 12, 14, 16, 18, 11, 13, 15, 17, 19, 21, 14, 16, 18, 11
Offset: 0

Views

Author

Reinhard Zumkeller, Jan 13 2008

Keywords

Comments

a(n) = A007953(A108773(n)) = A007953(A136613(n)).

A108203 Numbers n put into lexicographical order which are the concatenation of k and the sum of the digits of k.

Original entry on oeis.org

11, 22, 33, 44, 55, 66, 77, 88, 99, 101, 112, 123, 134, 145, 156, 167, 178, 189, 202, 213, 224, 235, 246, 257, 268, 279, 303, 314, 325, 336, 347, 358, 369, 404, 415, 426, 437, 448, 459, 505, 516, 527, 538, 549, 606, 617, 628, 639, 707, 718, 729, 808, 819, 909, 1001
Offset: 1

Views

Author

Keywords

Examples

			1 --> 11, 2 --> 22, 3 --> 33, ..., 9 --> 99, 10 --> 101, 11 --> 112, 12 --> 123,
..., 18 --> 189, 19 --> 1910 (ouch!), 20 --> 202, 21 --> 213, ...
		

Crossrefs

Cf. A062028, A064806. Equals A108773 sorted.

Programs

  • Mathematica
    f[n_] := FromDigits[ Join[ IntegerDigits[ n], IntegerDigits[Plus @@ IntegerDigits[ n]] ]]; t = {}; Do[t = Union[AppendTo[t, f[n]]], {n, 10^6}]

Extensions

a(55) from Rémy Sigrist, May 16 2019

A136613 Concatenation of (sum of digits of n) and n.

Original entry on oeis.org

0, 11, 22, 33, 44, 55, 66, 77, 88, 99, 110, 211, 312, 413, 514, 615, 716, 817, 918, 1019, 220, 321, 422, 523, 624, 725, 826, 927, 1028, 1129, 330, 431, 532, 633, 734, 835, 936, 1037, 1138, 1239, 440, 541, 642, 743, 844, 945, 1046, 1147, 1248, 1349, 550, 651, 752
Offset: 0

Views

Author

Reinhard Zumkeller, Jan 13 2008

Keywords

Crossrefs

Programs

  • Mathematica
    a[n_]:=FromDigits[Join[{DigitSum[n]},IntegerDigits[n]]] (* James C. McMahon, May 06 2025 *)

Formula

A136614(n) = A007953(a(n)) = A007953(A108773(n)).

A231963 Concatenate n with its UPC check digit, a(n) = 10*n + A237042(n).

Original entry on oeis.org

17, 24, 31, 48, 55, 62, 79, 86, 93, 109, 116, 123, 130, 147, 154, 161, 178, 185, 192, 208, 215, 222, 239, 246, 253, 260, 277, 284, 291, 307, 314, 321, 338, 345, 352, 369, 376, 383, 390, 406, 413, 420, 437, 444, 451, 468, 475, 482, 499, 505, 512, 529, 536, 543, 550, 567, 574, 581
Offset: 1

Views

Author

Alonso del Arte, Nov 15 2013

Keywords

Comments

Theoretically, a UPC check digit can be used with 1- or 2-digit numbers as well as numbers with more than 17 digits. There is probably no practical need for the former, while the latter would probably require a more robust error-detecting (if not error-correcting) mechanism.
However, the UPC check digit is a more robust mechanism than a simple digital root would be, as it guards against dyslexia when a seemingly scannable UPC code does not scan and the human operator has to type in the code (whether a cash register or a mobile scanner).
This is because to generate the check digit, the digits in the one's place, hundred's place, ten hundred's place, etc., are multiplied by 3. Thus, for example, 13 gives 0 for a check digit while 31 gives 4 for a check digit.
Some manufacturers that have or might have UPCs ending in the numbers shown above include H. J. Heinz (013000) and the Hershey Company (068000).
As a rule of thumb, the terms mostly advance in steps of 7, sometimes 17.

Examples

			a(13) = 130 because 1 * 1 + 3 * 3 = 10, giving a check digit of 0.
a(14) = 147 because 1 * 1 + 4 * 3 = 13, and -13 = 7 mod 10.
a(15) = 154 because 1 * 1 + 5 * 3 = 16, and -16 = 4 mod 10.
		

References

  • David Salomon, Coding for Data and Computer Communications. New York: Springer (2006): 41 - 42.

Crossrefs

Programs

  • PARI
    a(n) = 10*n + vecsum(digits(n,100)*31\-10) % 10; \\ Kevin Ryde, Oct 03 2023

Formula

a(n) = 10n + c(n), where c(n) = A237042(n) = -( (Sum_{i=1..floor(L/2)} d(2i-1)) + 3*(Sum_{j=0..floor(L/2)} d(2j)) ) mod 10, where L is how many digits n has, d(L - 1) is the most significant digit of n, ..., and d(0) is the one's place digit.

A302801 a(n) is the number whose digits result from the concatenation of the digits of n and the digits of the product of the digits of n.

Original entry on oeis.org

0, 11, 22, 33, 44, 55, 66, 77, 88, 99, 100, 111, 122, 133, 144, 155, 166, 177, 188, 199, 200, 212, 224, 236, 248, 2510, 2612, 2714, 2816, 2918, 300, 313, 326, 339, 3412, 3515, 3618, 3721, 3824, 3927, 400, 414, 428, 4312, 4416, 4520, 4624, 4728, 4832, 4936, 500, 515
Offset: 0

Views

Author

Michel Marcus, Apr 13 2018

Keywords

Examples

			For n=10, the digits of n are 1 and 0, their product is 0, and the concatenation gives 1 0 0.
		

Crossrefs

Programs

  • Mathematica
    Table[FromDigits[Join[IntegerDigits[n],IntegerDigits[Product[Part[IntegerDigits[n],k],{k,Length[IntegerDigits[n]]}]]]],{n,0,51}] (* Stefano Spezia, Aug 13 2023 *)
  • PARI
    mydigits(n) = if (n, digits(n), [0]);
    a(n) = my(d = mydigits(n)); fromdigits(concat(d, mydigits(prod(k=1, #d, d[k]))));
Showing 1-5 of 5 results.