GlenCalc

Number sequence calculator

Choose the type of sequence, give its first term and the step (or ratio), and say how many terms.

Your answer

Term 1039
Sum of the first 10 terms210
Terms3, 7, 11, 15, 19, 23, 27, 31, 35, 39

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How we worked it out

Updated as you change the numbers.

  1. aₙ = a₁ + (n − 1)d; Sₙ = n ÷ 2 × (2a₁ + (n − 1)d).

Method and assumptions

Arithmetic sequences add a constant difference; geometric sequences multiply by a constant ratio. The sum formulas avoid adding terms one by one. Fibonacci numbers here start 1, 1, 2, 3.

Questions

What is the 10th term of 3, 7, 11, …?

39, and the first 10 terms add up to 210.

Sources

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