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A249743 Main diagonal of square arrays A114881 and A249741. 2
1, 8, 34, 90, 208, 376, 628, 816, 1218, 1768, 2200, 2922, 3648, 4342, 5028, 5988, 7728, 8478, 10116, 11572, 12628, 14298, 16018, 17710, 21630, 23128, 24616, 26856, 28666, 30622, 35686, 38382, 42606, 44062, 50212, 52698, 56362, 60798, 63960, 68680, 73210, 76200, 82702, 85498, 90028, 92136, 101068, 109492, 114180, 119308, 126052, 133122 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

One less than the main diagonal of square arrays A083140 and A083221 formed from the sieve of Eratosthenes.

LINKS

Table of n, a(n) for n=1..52.

FORMULA

a(1) = 1, a(n) = (A000040(n) * A000040(2*(n-1))) - 1. [Where A000040(n) gives the n-th prime, p_n].

a(n) = A083140(n,n) - 1 = A083221(n,n) - 1.

a(n) = A083141(n+1)-1. [With the current starting offset 2 of A083141].

PROG

(Scheme) (define (A249743 n) (if (= 1 n) n (- (* (A000040 n) (A000040 (+ n n -2))) 1)))

CROSSREFS

One less than A083141.

Cf. A000040, A083140, A083221, A114881, A249741.

Sequence in context: A154516 A212744 A298174 * A298140 A301887 A208639

Adjacent sequences:  A249740 A249741 A249742 * A249744 A249745 A249746

KEYWORD

nonn

AUTHOR

Antti Karttunen, Nov 15 2014

STATUS

approved

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Last modified October 20 16:07 EDT 2021. Contains 348111 sequences. (Running on oeis4.)