Parity doublet states and alternating parity bands in [sup 149,151]Sm nuclei observed in [sup 148,150]Nd ([alpha],3[ital n][gamma]) reactions at [ital E][sub [alpha]]=37 and 35 MeV are presented here. Nineteen new transitions in [sup 149]Sm and sixteen in [sup 151]Sm have been observed in singles and [gamma]-[gamma]-[ital t]-r.f. coincidence experiments. Four alternating parity bands in [sup 149]Sm and two in [sup 151]Sm characterized by simplex quantum numbers are reported. The observed level schemes are interpreted in terms of octupole deformation. The energy difference due to parity splitting, collective rotational parameters, quasiparticle Routhians, single particle angular momentum alignments of bands with simplex quantum number [ital s]=[plus minus][ital i] in [sup 149]Sm and with [ital s]=[minus][ital i] in [sup 151]Sm have been calculated from the experimental results. From the [ital E]1, [ital E]2 branching ratios, the electric dipole moments are deduced to be [l angle][ital D][sub 0][r angle]=0.19[plus minus]0.08 [ital e] fm for [sup 149]Sm and [l angle][ital D][sub 0][r angle]=0.36[plus minus]0.11 [ital e] fm for [sup 151]Sm. The parameter [ital C][sub 1], a function of the symmetry energy coefficient, has been estimated for [sup 149]Sm from the liquid drop model of Strutinsky for deformed nucleus, and has been found to be [italmore » C][sub 1]=0.002003[sub [minus]0.000159][sup +0.000087] fm.« less