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.

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A249043 a(1) = 42; a(n+1) = a(n) + sum of decimal digits of a(n).

Original entry on oeis.org

42, 48, 60, 66, 78, 93, 105, 111, 114, 120, 123, 129, 141, 147, 159, 174, 186, 201, 204, 210, 213, 219, 231, 237, 249, 264, 276, 291, 303, 309, 321, 327, 339, 354, 366, 381, 393, 408, 420, 426, 438, 453, 465, 480, 492, 507, 519, 534, 546, 561, 573, 588, 609, 624, 636
Offset: 1

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Author

N. J. A. Sloane, Oct 30 2014

Keywords

References

  • D. R. Kaprekar, The Mathematics of the New Self Numbers, Privately Printed, 311 Devlali Camp, Devlali, India, 1963.

Crossrefs

Programs

  • Haskell
    a249043 n = a249043_list !! (n-1)
    a249043_list = iterate a062028 42
    -- Reinhard Zumkeller, Oct 31 2014

Formula

a(n+1) = A062028(a(n)). - Reinhard Zumkeller, Oct 31 2014

A151942 Table of Self / Colombian numbers and their descendents.

Original entry on oeis.org

1, 2, 3, 4, 6, 5, 8, 12, 10, 7, 16, 15, 11, 14, 9, 23, 21, 13, 19, 18, 20, 28, 24, 17, 29, 27, 22, 31, 38, 30, 25, 40, 36, 26, 35, 42, 49, 33, 32, 44, 45, 34, 43, 48, 53, 62, 39, 37, 52, 54, 41, 50, 60, 61, 64, 70, 51, 47, 59, 63, 46, 55, 66, 68, 74, 75, 77, 57, 58, 73, 72, 56
Offset: 1

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Author

Carl R. White, Jul 13 2009

Keywords

Comments

Initially resembles a permutation of the integers, but this is not the case. 101 is the first number to appear twice, descending from both 91 and 100: 91 + 9+1 = 100 + 1+0+0 = 101

Crossrefs

First column of table is the Self numbers: A003052; First through eighth rows are A004207, A016052, A007618, A006507, A016096, A036227, A036228 respectively.

Formula

T(r,0) are those numbers not of form n + sum of digits of n (Self numbers)
T(r,c) = T(r,c-1) + sum of digits of T(r,c-1)
Showing 1-2 of 2 results.