A120761 a(1) = a(2) = 1. a(n) = a(n-1) + (largest noncomposite {1 or prime} among the first n-2 terms of the sequence).

1, 1, 2, 3, 5, 8, 13, 18, 31, 44, 75, 106, 137, 168, 305, 442, 579, 716, 853, 990, 1843, 2696, 3549, 4402, 5255, 6108, 6961, 7814, 14775, 21736, 28697, 35658, 64355, 93052, 121749, 150446, 179143, 207840, 386983, 566126, 745269, 924412, 1103555

Offset

1,3

Links

Table of n, a(n) for n=1..43.

Example

Among the first 10 terms of the sequence, 31 is the largest noncomposite. So a(12) = a(11) + 31 = 75 + 31 = 106.

Maple

isA008578 := proc(n) if n = 1 or isprime(n) then true ; else false ; fi ; end: A120761 := proc(nmin) local a, lnpr, k; a := [1, 1, 2] ; while nops(a) < nmin do lnpr :=0 ; for k in [op(1..nops(a)-1, a)] do if isA008578(k) then lnpr := max(lnpr, k) ; fi ; od: a := [op(a), a[ -1]+lnpr] ; od: RETURN(a) ; end: A120761(80) ; # R. J. Mathar, Sep 18 2007

Crossrefs

Cf. A120760.

Sequence in context: A081612 A343484 A301754 * A355513 A281967 A178741

Adjacent sequences: A120758 A120759 A120760 * A120762 A120763 A120764

Keyword

nonn

Author

Leroy Quet, Jul 03 2006

Extensions

More terms from R. J. Mathar, Sep 18 2007

Status

approved