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 A061213 a(n) = product of first n triangular numbers (A000217) + 1. 1
 2, 4, 19, 181, 2701, 56701, 1587601, 57153601, 2571912001, 141455160001, 9336040560001, 728211163680001, 66267215894880001, 6958057668962400001, 834966920275488000001, 113555501157466368000001 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 LINKS Harry J. Smith, Table of n, a(n) for n=1,...,100 FORMULA a(n) = {n(n+1)/2}*{a(n-1)-1}+1 EXAMPLE a(6) = 1 * 3 * 6 * 10 *15 * 21 + 1 = 56701 MAPLE for n from 1 to 30 do printf(`%d, `, 1+product(j*(j+1)/2, j=1..n)) od: PROG (PARI) { for (n=1, 100, if (n>1, a=(n*(n + 1)/2)*(a - 1) + 1, a=2); write("b061213.txt", n, " ", a) ) } \\ Harry J. Smith, Jul 19 2009 CROSSREFS Equals A006472 + 1. Sequence in context: A191563 A046082 A048774 * A063458 A332991 A132530 Adjacent sequences: A061210 A061211 A061212 * A061214 A061215 A061216 KEYWORD nonn AUTHOR Amarnath Murthy, Apr 21 2001 EXTENSIONS More terms from James A. Sellers, Apr 24 2001 OFFSET changed from 0,1 to 1,1 and EXAMPLE corrected by Harry J. Smith, Jul 19 2009 STATUS approved

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Last modified June 6 15:10 EDT 2023. Contains 363147 sequences. (Running on oeis4.)