|
| |
| |
|
|
|
0, 1, 4, 6, 10, 15, 22, 28, 36, 45, 56, 66, 78, 91, 106, 120, 136, 153, 172, 190, 210, 231, 254, 276, 300, 325, 352, 378, 406, 435, 466
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,3
|
|
|
FORMULA
| a(n) = SUM[i=1..n] A116966(n). a(n) = SUM[i=1..n] (n + {1,2,0,1} according as n == {0,1,2,3} mod 4). a(n) = A000217(n) = n*(n+1)/2 unless n == 2 mod 4 in which case a(n) = A000217(n)+1 = (n*(n+1)/2)+1.
|
|
|
EXAMPLE
| a(1) = 1 = A000217(1).
a(2) = 1+3 = 4 = A000217(2)+1.
a(3) = 1+3+2 = 6 = A000217(3).
a(4) = 1+3+2+4 = 10 = A000217(4).
a(5) = 1+3+2+4+5 = 15 = A000217(5).
a(6) = 1+3+2+4+5+7 = 22 = A000217(6)+1.
a(27) = 1+3+2+4+5+7+6+8+9+11+10+12+13+15+14+16+17+19+18+20+21+23+22+24+25+27+26 = 378 = A000217(27).
|
|
|
CROSSREFS
| Cf. A000217, A116966.
Sequence in context: A076957 A179445 A121214 * A004399 A186777 A028282
Adjacent sequences: A116993 A116994 A116995 * A116997 A116998 A116999
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| Jonathan Vos Post (jvospost3(AT)gmail.com), Apr 02 2006
|
| |
|
|
