# Mathemetic series 1, 3, 6, 10, 15, 21, 28, 36, 45,__? [closed]

I currently looking what will be the next value to 45 as per given series.

Is there any specific equation available?

## closed as off-topic by boboquack, Alconja, Glorfindel, JMP, Rubio♦Jun 19 '17 at 7:15

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• "This question is off-topic as it appears to be a mathematics problem, as opposed to a mathematical puzzle. For more info, see "Are math-textbook-style problems on topic?" on meta." – boboquack, Alconja, Glorfindel, JMP, Rubio
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• Look at the differences between adjacent numbers. Perhaps you can see a pattern. – M Oehm Jun 18 '17 at 19:05
• So it means my answer will be 55? Correct? – Shyam Shingadiya Jun 18 '17 at 19:08
• You might want to investigate triangular numbers in your spare time. – boboquack Jun 18 '17 at 20:20

$$t_n = \sum_{i = 1}^{n}i = \frac{n\cdot(n+1)}2$$
• @MikeQ Yes of course. We can also simply state $t_n = t_{n-1} + n$ with $t_1 = 1$ – Paul Evans Jun 18 '17 at 22:53