Pumpkins need rich soil and adequate moisture to fill out. Approximately 7 seeds/gram.
Hints:

Sow 4-5 seeds 2 cm [1"] deep in hills 2 m [6'] apart.

Thin to the two or three strongest plants.

Jack O' Lantern - 110 days. Fruits are round to oval shapes 4-7 kg [10-15 lbs] Skin is bright orange, smooth, firm and thick. Excellent for carving. Approximate seeds per gram - 3 to 5. Seeding rate 7 grams per 100' row or 1kg per acre.