A249743 Main diagonal of square arrays A114881 and A249741.

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

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