A083525 a(1) = 1, a(n) = a(n-1)*n if n is composite, a(n) = a(n-1) + n if n is a prime.

1, 3, 6, 24, 29, 174, 181, 1448, 13032, 130320, 130331, 1563972, 1563985, 21895790, 328436850, 5254989600, 5254989617, 94589813106, 94589813125, 1891796262500, 39727721512500, 874009873275000, 874009873275023, 20976236958600552

Offset

1,2

Links

Michael De Vlieger, Table of n, a(n) for n = 1..529

Maple

a := proc(n) option remember: if n=1 then RETURN(1) fi: if isprime(n) then RETURN(a(n-1)+n) else RETURN(a(n-1)*n) fi: end: for n from 1 to 50 do printf(`%d, `, a(n)) od: # James A. Sellers, May 19 2003

Mathematica

nxt[{a_, n_}]:={If[PrimeQ[n+1], a+n+1, a(n+1)], n+1}; Transpose[ NestList[ nxt, {1, 1}, 30]][[1]] (* Harvey P. Dale, Jun 24 2014 *)

Crossrefs

Cf. A083524.

Sequence in context: A013212 A013218 A101738 * A106213 A129520 A330300

Adjacent sequences: A083522 A083523 A083524 * A083526 A083527 A083528

Keyword

easy,nonn

Author

Amarnath Murthy, May 05 2003

Extensions

More terms from James A. Sellers, May 19 2003

Status

approved