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A266742 Irregular triangle read by rows: T(n,k) = floor(n/(prime(k)-1)), n>=1, 1 <= k <= pi(n+1), where pi is A000720. 3
1, 2, 1, 3, 1, 4, 2, 1, 5, 2, 1, 6, 3, 1, 1, 7, 3, 1, 1, 8, 4, 2, 1, 9, 4, 2, 1, 10, 5, 2, 1, 1, 11, 5, 2, 1, 1, 12, 6, 3, 2, 1, 1, 13, 6, 3, 2, 1, 1, 14, 7, 3, 2, 1, 1, 15, 7, 3, 2, 1, 1, 16, 8, 4, 2, 1, 1, 1, 17, 8, 4, 2, 1, 1, 1, 18, 9, 4, 3, 1, 1, 1, 1 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..83.

H. T. Davis, Tables of the Mathematical Functions, Vols. 1 and 2, 2nd ed., 1963, Vol. 3 (with V. J. Fisher), 1962; Principia Press of Trinity Univ., San Antonio, TX. [Annotated scan of pages 204-208 of Volume 2.] See Table 1 on page 205.

EXAMPLE

Triangle begins:

[1]

[2, 1]

[3, 1]

[4, 2, 1]

[5, 2, 1]

[6, 3, 1, 1]

[7, 3, 1, 1]

[8, 4, 2, 1]

[9, 4, 2, 1]

[10, 5, 2, 1, 1]

[11, 5, 2, 1, 1]

[12, 6, 3, 2, 1, 1]

[13, 6, 3, 2, 1, 1]

[14, 7, 3, 2, 1, 1]

...

MAPLE

with(numtheory);

f:=n->[seq(floor(n/(ithprime(i)-1)), i=1..pi(n+1))];

for n from 1 to 20 do lprint(f(n)); od:

CROSSREFS

Cf. A000720, A002443, A002444, A266743.

Sequence in context: A319848 A233772 A056538 * A120385 A216477 A195836

Adjacent sequences:  A266739 A266740 A266741 * A266743 A266744 A266745

KEYWORD

nonn,tabf

AUTHOR

N. J. A. Sloane, Jan 08 2016

STATUS

approved

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Last modified March 20 13:18 EDT 2019. Contains 321345 sequences. (Running on oeis4.)