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A309721 Number of right angles between the segments that are turned "on" when representing n on a 7-segment (calculator) display. 0
4, 0, 4, 4, 3, 4, 6, 1, 8, 6, 4, 0, 4, 4, 3, 4, 6, 1, 8, 6, 8, 4, 8, 8, 7, 8, 10, 5, 12, 10, 8, 4, 8, 8, 7, 8, 10, 5, 12, 10, 7, 3, 7, 7, 6, 7, 9, 4, 11, 9, 8, 4, 8, 8, 7, 8, 10, 5, 12, 10, 10, 6, 10, 10, 9, 10, 12, 7, 14, 12, 5, 1, 5, 5, 4, 5, 7, 2, 9, 7, 12, 8, 12, 12, 11, 12, 14, 9, 16, 14, 10, 6, 10, 10, 9, 10, 12, 7 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,1

COMMENTS

The display is the one described in A006942 (see also the example section below).

LINKS

Table of n, a(n) for n=0..97.

FORMULA

a(n) = a(floor(n/10)) + a(n mod 10), for n > 9 (a formula by Reinhard Zumkeller, same for A006942 and A010371).

EXAMPLE

To illustrate a(0),...,a(9):

   _     _  _       _   _   _   _   _

  | | |  _| _| |_| |_  |_    | |_| |_|

  |_| | |_  _|   |  _| |_|   | |_|  _|

.

MATHEMATICA

Evaluate[Table[a[n], {n, 0, 9}]]={4, 0, 4, 4, 3, 4, 6, 1, 8, 6};

a[n_/; n>9]:=a[Floor[n/10]]+a[Mod[n, 10]]; a/@Range[0, 100] (* or *)

Table[Total[IntegerDigits[n]/.{0->4, 1->0, 2->4, 3->4, 4-> 3, 5->4, 7->1, 9->6}], {n, 0, 100}]

CROSSREFS

Cf. A006942, A010371, A063720, A277116.

Sequence in context: A152856 A031362 A198414 * A110854 A278086 A021716

Adjacent sequences:  A309718 A309719 A309720 * A309722 A309723 A309724

KEYWORD

nonn,base,easy

AUTHOR

Ivan N. Ianakiev, Aug 14 2019

STATUS

approved

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Last modified February 27 10:09 EST 2021. Contains 341649 sequences. (Running on oeis4.)