Jokshan
Jokshan (Hebrew: יָקשָׁן yoqšān). According to the Bible he was a son of Abraham and his either wife[1] or concubine[2] Keturah, whom he wed after the death of Sarah.[3] Jokshan had five brothers: Zimran, Medan, Midian, Ishbak and Shuah;[4] as well as two half brothers: Ishmael and Isaac. He was Keturah's second son and Abraham's fourth.
Josephus records that "Abraham contrived to settle them in colonies; and they took possession of Troglodytis and the country of Arabia Felix, as far as it reaches to the Red Sea."[5] Abraham in all probability, tried to keep them apart from Isaac to avoid conflict while fulfilling God's commission to spread out and inhabit the globe.[6][7][8]
Jokshan became the father of Sheba and Dedan. Dedan had three sons, named Asshurim, Letushim, and Leummim.[9]
Sheba and Dedan to whom do they belong their mentioned under two different individuals as sons
Raamah
Gen 10:7 And the sons of Cush; Seba, and Havilah, and Sabtah, and Raamah, and Sabtecha: and the sons of Raamah; Sheba, and Dedan.
1Ch 1:9 And the sons of Cush; Seba, and Havilah, and Sabta, and Raamah, and Sabtecha. And the sons of Raamah; Sheba, and Dedan.
Jokshan
Gen 25:3 And Jokshan begat Sheba, and Dedan. And the sons of Dedan were Asshurim, and Letushim, and Leummim.
1Ch 1:32 Now the sons of Keturah, Abraham's concubine: she bare Zimran, and Jokshan, and Medan, and Midian, and Ishbak, and Shuah. And the sons of Jokshan; Sheba, and Dedan.