OFFSET
1,1
EXAMPLE
2; 7,2; 1,7,2; 8,1,7,2; 2,8,1,7,2;... (reverse order of 2; 2.7; 2.71; 2.718; 2.7182;...)
MATHEMATICA
Module[{nn=20, e}, e=RealDigits[E, 10, (nn(nn+1))/2][[1]]; Reverse/@Table[ Take[ e, n], {n, nn}]]//Flatten (* Harvey P. Dale, Apr 19 2020 *)
PROG
(PARI) a(n)=if(n<1, 0, default(realprecision, n+2); floor(exp(1)*10^(n-1))%10); b(n)=1+binomial(1+floor(1/2+sqrt(2*n)), 2)-n; for(n=1, 120, print1(a(b(n)), ", ")
CROSSREFS
KEYWORD
AUTHOR
Herman Jamke (hermanjamke(AT)fastmail.fm), Jul 07 2004
STATUS
approved