Annual Appeal: Please make a donation (tax deductible in USA) to keep the OEIS running. Over 4500 articles have referenced us, often saying "we would not have discovered this result without the OEIS".
1,2
T. D. Noe, Table of n, a(n) for n = 1..10000
(PARI) a(n)=sigma(n+2)-2*sigma(n+1)+sigma(n) \\ Charles R Greathouse IV, Mar 09 2014
Cf. A000203, A053222, A053228, A053229, A053247, A053248.
Sequence in context: A059186 A034702 A167206 * A153383 A177093 A164903
Adjacent sequences: A053220 A053221 A053222 * A053224 A053225 A053226
sign
Asher Auel (asher.auel(AT)reed.edu) Jan 06 2000
approved