A144192 (0, 1, 2^2, 2*3, 2^3, 3^2, 2*5, 2^2*3, 2*7, 3*5, 2^4, 2*3^2, ...) becomes (0+1, 2+2, 2+3, 2+3, 3+2, 2+5, 2+2, 3+2, 7+3, 5+2, 4+2, 3+2, ...).

1, 4, 5, 5, 5, 7, 4, 5, 10, 7, 6, 5, 4, 8, 9, 13, 6, 7, 15, 6, 4, 9, 8, 7, 14, 19, 12, 4, 5, 21, 16, 5, 7, 10, 4, 14, 7, 25, 6, 10, 4, 7, 20, 4, 15, 6, 16, 5, 10, 21, 31, 5, 7, 34, 9, 8, 18, 5, 13, 19, 26, 7, 9, 6, 4, 40, 7, 4, 26, 13, 16, 6, 8, 6, 43, 5, 12, 19, 46, 31, 14, 5, 7, 20, 4, 26, 33

Offset

1,2

Links

Table of n, a(n) for n=1..87.

Example

3 + 2 = 5 = a(12),
2 + 2 = 4 = a(13),
5 + 3 = 8 = a(14),
5 + 2 = 7 = a(15),
7 + 2 = 9 = a(16),
11 + 2 = 13 = a(17),
3 + 3 = 6 = a(18),
5 + 2 = 7 = a(19),
2 + 13 = 15 = a(20),
3 + 3 = 6 = a(21),
2 + 2 = 4 = a(22),
7 + 2 = 9 = a(23), etc.

Maple

pflat := proc(nmax) local a, ifs, n, p, c ; a := [0, 1] ; for n from 2 to nmax do if not isprime(n) then ifs := ifactors(n)[2] ; for p in ifs do a := [op(a), op(1, p)] ; if op(2, p) > 1 then a := [op(a), op(2, p)] ; fi; od: fi; od: a ; end: L := pflat(300) ; for n from 1 to nops(L)-2 by 2 do printf("%d, ", op(n, L) + op(n+1, L) ) ; end do: # R. J. Mathar, Apr 29 2010

Crossrefs

Cf. A141468.

Sequence in context: A018245 A264936 A103671 * A029909 A141276 A088202

Adjacent sequences: A144189 A144190 A144191 * A144193 A144194 A144195

Keyword

nonn

Author

Juri-Stepan Gerasimov, Nov 20 2008

Extensions

Corrected (a(15) removed, former a(65) replaced) by R. J. Mathar, Apr 29 2010

Status

approved