A241494 Pyramid Top Numbers: write the decimal digits of 'n' (a nonnegative integer) and take successive absolute differences ("pyramidalization"). The number at the top of the pyramid is 'a(n)'.

0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 2, 1, 0, 1, 2, 3, 4, 5, 6, 7, 3, 2, 1, 0, 1, 2, 3, 4, 5, 6, 4, 3, 2, 1, 0, 1, 2, 3, 4, 5, 5, 4, 3, 2, 1, 0, 1, 2, 3, 4, 6, 5, 4, 3, 2, 1, 0, 1, 2, 3, 7, 6, 5, 4, 3, 2, 1, 0, 1, 2, 8, 7, 6, 5

Offset

0,3

Comments

Through the so-called "pyramidalization" process (see A227876), a given nonnegative integer is expanded into its digits and transformed into a pyramid of successive absolute differences between digits. The present sequence is built only with the top number 'a(n)' generated from its correspondent nonnegative integer 'n'.

Links

Filipi R. de Oliveira, Table of n, a(n) for n = 0..9999

Formula

a(n)=n, if 0<=n<=9.

a(n)=|mod(n;10)-floor(n/10)|, if 10<=n<=99.

Example

If n=1735, a(n)=0:
______0 ------>a(n)
____2_:_2
__6_:_4_:_2
1_:_7_:_3_:_5

Crossrefs

Cf. A227876 for the pyramidalization process.

Cf. A076313 - its first 100 terms have the same absolute value, diverging afterwards; cf. A225693 and A055017 (A040997) for the same reason.

Sequence in context: A325479 A001073 A274580 * A076313 A055017 A225693

Adjacent sequences: A241491 A241492 A241493 * A241495 A241496 A241497

Keyword

base,nonn,easy,look

Author

Filipi R. de Oliveira, Apr 24 2014

Status

approved