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A122257 Characteristic function of Pierpont primes (A005109). 4
0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Antti Karttunen, Table of n, a(n) for n = 1..65537

Eric Weisstein's World of Mathematics, Pierpont Prime

Index entries for characteristic functions

FORMULA

a(n) = A010051(n) * A065333(n-1).

a(n) = if (n is prime) and (n-1 is 3-smooth) then 1 else 0.

a(n) = if n=1 then 0 else A122258(n) - A122258(n-1);

a(A122259(n)) = 0, a(A005109(n)) = 1.

PROG

(Scheme)

(define (A122257 n) (if (= 1 n) 0 (if (= 1 (A065333 (- n 1))) (A010051 n) 0)))

(define (A065333 n) (if (= 1 (A038502 (A000265 n))) 1 0))

;; Antti Karttunen, Dec 07 2017

CROSSREFS

Cf. A005109, A010051, A065333, A122258 (partial sums).

Sequence in context: A010060 A316569 A118247 * A129950 A010051 A131929

Adjacent sequences:  A122254 A122255 A122256 * A122258 A122259 A122260

KEYWORD

nonn

AUTHOR

Reinhard Zumkeller, Aug 29 2006

STATUS

approved

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Last modified November 20 06:06 EST 2018. Contains 317385 sequences. (Running on oeis4.)