Carbon134
Carbon134 is a hypothetical or theoretical isotope of carbon. The most common isotope of carbon is carbon-12, which has six protons and six neutrons. Carbon-13 is a stable isotope with six protons and seven neutrons. Carbon-14 is a radioactive isotope with six protons and eight neutrons, commonly used in radiocarbon dating. Isotopes of an element have the same number of protons but different numbers of neutrons. Therefore, a hypothetical isotope like carbon-134 would possess six protons and a total of 134 nucleons (protons plus neutrons).
The existence of an isotope with such a large number of neutrons for carbon is highly improbable