There's something instantly and persistently likable about the San Francisco-based Nancy Karp + Dancers troupe--a beguiling, innocent warmth. It was this quality more than anything else that got one past some choreographic drawbacks in the group's area debut Thursday night at the Washington Project for the Arts.

The program--four works for ensembles ranging from three dancers to the troupe's full complement of six--put director-choreographer Karp squarely in the camp of post-modern pattern dance, with rhythmic ostinatos, geometrical configurations and permutational structures as the basis of each piece. What Karp gives us, however, seems quintessentially West Coast--something decidedly sunnier, looser and more blissed out than its East Coast counterparts. From an Atlantic seaboard perspective, too, Karp's work looks like a throwback to the trends of the mid-'70s; it's more doggedly minimalist, more stripped down, than what the postmoderns here are doing these days.

Karp's choreography falls somewhere between that of Lucinda Childs and that of Laura Dean, the two best-known parallels. Formally, it's closer to Childs in its mathematical substrate, but on an expressive plane it seems more akin to Dean, in its lyricism and geniality. "Relay, Relay," the evening's one premiere, had its quartet of dancers moving in circles and crosses, with stamped accents and soft, winglike arm flaps for embellishment. "Passing By," to an agreeable pulse music score by Paul Dresher, featured a trio of dancers in mostly rectangular grid patterns, with shifts of tempo marking off sections.

In the engaging "Reminiscence," Karp's own mellow score for a pair of homemade, gamelan-style metallophones helped lend a blithe veneer to the angles, arcs and diagonals of the dancing. "Jumping Phase" restricted itself to a single row of dancers bouncing in place as they vocalized a madrigalian play of syllables--"ha," "hey," and "ho."

All this was sweetly euphoric and sporadically interesting, but also on the pallid side and not infrequently dull. The dancers projected an affable, commune-like rapport, and performed with obvious conviction. But the choreography rarely progressed from a relatively flat sequence of modules into a sense of advancing momentum or organic growth. Pattern dances need striking, consistently engrossing patterns and a strong overall formal motivation; otherwise they're apt to turn into choreographic wallpaper, a danger the Karp troupe wasn't always able to avert.

The group's final performance is this evening.