A370010 a(n) is the greatest prime less than 4*prime(n).

7, 11, 19, 23, 43, 47, 67, 73, 89, 113, 113, 139, 163, 167, 181, 211, 233, 241, 263, 283, 283, 313, 331, 353, 383, 401, 409, 421, 433, 449, 503, 523, 547, 547, 593, 601, 619, 647, 661, 691, 709, 719, 761, 769, 787, 787, 839, 887, 907, 911, 929, 953, 953, 997

Offset

1,1

Links

Table of n, a(n) for n=1..54.

Example

7 < 4*2 < 11 < 4*3 < 13 < 17 < 19  < 5*3 < 23, so (a(1), a(2), a(3)) = (7,11,19).

Mathematica

Table[Prime[PrimePi[4*Prime[n]]], {n, 1, 200}]

Prog

(PARI) a(n) = precprime(4*prime(n)); \\ Michel Marcus, Feb 10 2024

Crossrefs

Cf. A000040, A001749, A059786, A059788, A370008, A370011.

Sequence in context: A065312 A343142 A235727 * A141337 A192187 A053403

Adjacent sequences: A370007 A370008 A370009 * A370011 A370012 A370013

Keyword

nonn

Author

Clark Kimberling, Feb 09 2024

Status

approved