C PNORMJ    SOURCE    CHAT      05/01/13    02:15:32     5004
      FUNCTION PNORMJ (N,ALPHA,BETA)
      IMPLICIT INTEGER(I-N)
      IMPLICIT REAL*8 (A-H,O-Z)
      ONE   = 1.D0
      TWO   = 2.D0
      DN    = DBLE(N)
      CONST = ALPHA+BETA+ONE
      IF (N.LE.1) THEN
         PROD   = GAMMAF(DN+ALPHA)*GAMMAF(DN+BETA)
         PROD   = PROD/(GAMMAF(DN)*GAMMAF(DN+ALPHA+BETA))
         PNORMJ = PROD * TWO**CONST/(TWO*DN+CONST)
         RETURN
      ENDIF
      PROD  = GAMMAF(ALPHA+ONE)*GAMMAF(BETA+ONE)
      PROD  = PROD/(TWO*(ONE+CONST)*GAMMAF(CONST+ONE))
      PROD  = PROD*(ONE+ALPHA)*(TWO+ALPHA)
      PROD  = PROD*(ONE+BETA)*(TWO+BETA)
      DO 100 I=3,N
         DINDX = DBLE(I)
         FRAC  = (DINDX+ALPHA)*(DINDX+BETA)/(DINDX*(DINDX+ALPHA+BETA))
         PROD  = PROD*FRAC
 100  CONTINUE
      PNORMJ = PROD * TWO**CONST/(TWO*DN+CONST)
      RETURN
      END