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

Author

Antti Karttunen, Nov 15 2014

Keywords

• nonn

Comments

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

Crossrefs

One less than A083141.

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

Programs

Scheme

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

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].