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A278167 a(n) = number of primes encountered before reaching 0 when starting from k = ((n+1)^2)-1 and iterating map k -> k - A002828(k). 6
1, 1, 2, 2, 2, 3, 5, 6, 7, 7, 9, 10, 12, 12, 15, 17, 17, 20, 20, 22, 22, 23, 27, 29, 32, 34, 38, 40, 40, 43, 46, 48, 53, 56, 60, 63, 66, 69, 71, 75, 77, 79, 83, 86, 89, 92, 98, 101, 102, 105, 109, 111, 117, 120, 123, 125, 130, 135, 140, 145, 149, 152, 159, 163, 167, 173, 177, 179, 183, 189, 194, 199, 204, 208, 215, 219, 223, 230, 234 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

COMMENTS

a(n) = number of terms of A277888 less than (n+1)^2.

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..10000

FORMULA

a(1) = A277487(1); for n > 1, a(n) = A277487(n) + a(n-1).

EXAMPLE

For n=4, starting from k = ((4+1)^2)-1, and iterating k -> A255131(k), yields 24 -> 21 -> 18 -> 16 -> 15 -> 11 -> 8 -> 6 -> 3 before 0 is reached. Of these numbers only 11 and 3 are primes, thus a(4) = 2.

PROG

(Scheme) (definec (A278167 n) (if (= 1 n) (A277487 n) (+ (A277487 n) (A278167 (- n 1)))))

CROSSREFS

Partial sums of A277487.

Cf. A002828, A255131, A278166, A278168, A277888.

Sequence in context: A035658 A077018 A007918 * A239470 A320786 A126111

Adjacent sequences:  A278164 A278165 A278166 * A278168 A278169 A278170

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 13 2016

STATUS

approved

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Last modified June 5 09:32 EDT 2020. Contains 334829 sequences. (Running on oeis4.)