OFFSET
1,2
REFERENCES
Norman Sullivan, Test Your Own IQ, Workman Publishing Co. New York, NY, 1994, pp. 48, 50.
LINKS
Harry J. Smith, Table of n, a(n) for n = 1..2000
MATHEMATICA
Array[{#, (4 + Boole[EvenQ@ #]) #} &@ PolygonalNumber@ # &, 28] // Flatten (* Michael De Vlieger, Jul 01 2018 *)
PROG
(PARI) { f="b061727.txt"; for (n=1, 1000, a=n*(n + 1)/2; if (a%2, t=a*4, t=a*5); write(f, 2*n - 1, " ", a); write(f, 2*n, " ", t) ) } \\ Harry J. Smith, Jul 27 2009
CROSSREFS
KEYWORD
nonn,dumb,easy
AUTHOR
Jason Earls, May 05 2001
EXTENSIONS
More terms from David Wasserman, Jun 25 2002
STATUS
approved