A113161 a(1) = 1; for n > 1, a(n) = largest prime <= a(n-1) + n - 1.

1, 2, 3, 5, 7, 11, 17, 23, 31, 37, 47, 53, 61, 73, 83, 97, 113, 127, 139, 157, 173, 193, 211, 233, 257, 281, 307, 331, 359, 383, 409, 439, 467, 499, 523, 557, 593, 619, 653, 691, 727, 761, 797, 839, 883, 919, 953, 997, 1039, 1087, 1129, 1171, 1223, 1259, 1307

Offset: 1

Author

Leroy Quet, Jan 05 2006

Keywords

• nonn

Examples

			a(7) = 17. So a(8) = the largest prime <= 17 + 7 = 24, which is 23.
		

Links

• Harvey P. Dale, Table of n, a(n) for n = 1..1000

Crossrefs

Cf. A093503.

Programs

Mathematica

PrevPrim[n_] := Block[{k = n - 1}, While[ !PrimeQ[k], k-- ]; k]; a[1] = 1; a[n_] := a[n] = PrevPrim[a[n - 1] + n]; Array[a, 55] (* Robert G. Wilson v *)
a[1]=1;a[n_]:=NextPrime[a[n-1]+n,-1];Table[a[n],{n,55}] (* James C. McMahon, Jun 16 2024 *)
nxt[{n_,a_}]:={n+1,If[PrimeQ[a+n],a+n,NextPrime[a+n,-1]]}; NestList[nxt,{1,1},60][[;;,2]] (* Harvey P. Dale, Dec 15 2024 *)

PARI

{print1(a=1,",");for(n=2,55,print1(a=precprime(a+n-1),","))} \\ Klaus Brockhaus, Jan 06 2006

Extensions

More terms from Klaus Brockhaus and Robert G. Wilson v, Jan 06 2006