A060729 a(n+1) = a(n) + a(n minus the number of terms of the same parity as n so far).

1, 2, 3, 4, 6, 9, 12, 16, 19, 25, 31, 37, 49, 55, 74, 83, 108, 120, 145, 161, 198, 217, 266, 291, 346, 377, 451, 482, 565, 602, 710, 765, 885, 940, 1085, 1159, 1357, 1431, 1697, 1771, 2117, 2191, 2642, 2725, 3207, 3290, 3855, 3963, 4673, 4781

Offset

1,2

Links

Ivan Neretin, Table of n, a(n) for n = 1..10000

Example

a(5) = a(4) + a(4 - the number of even terms so far) = a(4) + a(4-2) = 4 + 2 = 6.

Mathematica

a[ 1 ] = 1; a[ 2 ] = 2; a[ n_ ] := a[ n ] = Block[ {e = 0}, Do[ If[ EvenQ[ a[ k ] ], e++ ], {k, 1, n - 1} ]; If[ OddQ[ n ], a[ n - 1 ] + a[ n - 1 - e ], a[ n - 1 ] + a[ e ] ] ]; Table[ a[ n ], {n, 1, 50} ]

Crossrefs

Cf. A006336, A006604.

Sequence in context: A112249 A204502 A062437 * A229169 A155510 A073576

Adjacent sequences: A060726 A060727 A060728 * A060730 A060731 A060732

Keyword

nonn

Author

Robert G. Wilson v, Apr 22 2001

Status

approved