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A064188 Sum_{ i = 0 .. floor(n/2)} binomial (n - i*(i-1)/2, i). 1
1, 3, 4, 8, 12, 18, 27, 40, 58, 83, 118, 195, 242, -1387, -338, 75876, 44491, -3099115, -2028539, 129829195, 91749709, -5687984421, -4236497556, 263653557716, 204087552038, -12979768392096, -10348229609729, 679042377362009, 554161706136054, -37712174126966326 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,2

LINKS

Table of n, a(n) for n=0..29.

MATHEMATICA

Table[ Sum[ Binomial[ n - i*(i - 1)/2, i ], {i, 0, Floor[ n/2 ] } ], {n, 1, 30} ]

CROSSREFS

Cf. A063978.

Sequence in context: A085635 A077434 A076136 * A229990 A147620 A195746

Adjacent sequences:  A064185 A064186 A064187 * A064189 A064190 A064191

KEYWORD

sign

AUTHOR

Helmut Schnitzspan (HSchnitzspan(AT)gmx.de), Sep 05 2001

EXTENSIONS

More terms from Robert G. Wilson v, Sep 06 2001

STATUS

approved

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Last modified October 18 07:58 EDT 2018. Contains 316307 sequences. (Running on oeis4.)