A276201 Largest prime < A019518(n).

19, 233, 2351, 235699, 23571103, 2357111297, 235711131709, 23571113171891, 2357111317192243, 235711131719232929, 23571113171923293127, 2357111317192329313727, 235711131719232931374061, 23571113171923293137414303, 2357111317192329313741434739, 235711131719232931374143475271

Offset: 2

Author

Ilya Gutkovskiy, Aug 24 2016

Keywords

• nonn
• base

Comments

The complement of A074366.

Examples

			a(5) = 235699, because this is the largest prime less than 235711 (concatenation of first 5 primes, written in decimal system).
		

Links

• Eric Weisstein's World of Mathematics, Previous Prime

Crossrefs

Cf. A000040, A000720, A019518, A074366, A151799.

Programs

Mathematica

Table[NextPrime[FromDigits[Flatten[IntegerDigits[Prime[Range[n]]]]], -1], {n, 2, 17}]

Formula

a(n) = A151799(A019518(n)).

a(n) = A000040(A000720(A019518(n)-1)).